Elastomer composition containing mercaptofunctional silane and process for making same

ABSTRACT

A filled elastomer composition comprises:
     a) at least one rubber component;   b) at least one particulate filler; and,   c) at least one mercaptofunctional silane of a particular structure.

FIELD OF THE INVENTION

The present disclosure relates to elastomeric materials and articlestherefrom containing mercaptofunctional silanes and/or mixtures ofmercaptofunctional silanes and processes for making such elastomericmaterials and articles. These silanes reduce or eliminate the generationof volatile organic compounds (VOC's) during use, aid in the processingof filled elastomeric materials and enhance the end-use properties ofthe filled elastomers.

DESCRIPTION OF THE RELATED ART

Mercaptosilanes and their use as coupling agents in filled elastomersare known in the art. However, the heretofore known silanes are veryreactive with conventional fillers and elastomers and are thereforedifficult to use. When known silanes are used at levels necessary toachieve optimum coupling of filler to the host elastomer, the uncuredfilled elastomer typically exhibits short scorch times and poorlydispersed filler. Long scorch times are necessary for mixing of thefiller and other ingredients with the elastomer, extrusion of theuncured elastomer and fabrication of articles therefrom withoutpremature crosslinking or formation of high viscosity compounds. Gooddispersion of filler is required to achieve satisfactory end-useproperties such as weatherability, wear, tear-resistance, and so on.Known silanes are also derived from monoalcohols that generate volatileorganic compound (VOC) emissions during their fabrication and use.

U.S. Pat. Nos. 6,548,594 and 6,849,754 describe mercaptosilane couplingagents containing C₉-C₃₀ alkoxy groups. Although these compounds offerreduced VOC emissions, the processing of rubber containing them andtheir performance as coupling agents could stand improvement.

In addition to the need to reduce VOC's during the preparation ofinorganic filled elastomers, there is also a need to improve thedispersion of the inorganic fillers in the elastomers while maintainingprocessability of the compositions. Better dispersion improves theperformance of cured articles made with the filled elastomers, such astires, by reducing their rolling resistance, heat build-up and wear.

Glycol derivatives of organosilanes are known in the art. Recently, thepresent inventors addressed in U.S. patent application Ser. Nos.11/358,550, 11/358,818, 11/358,369, and 11/358,861 the scorch, VOCemissions and coupling performance of filled elastomers usingorganofunctional silanes or mixtures of organofunctional silanes thatcontain both blocked and free mercaptan groups. The present inventorsalso addressed in U.S. patent applications Ser. Nos. 11/505,055,11/505,166, and 11/505,178 the scorch, VOC emissions and couplingperformance of filled elastomers using organofunctional silanes ormixtures of organofunctional silanes that contain both dispersing andfree mercaptan groups. In addition, the present inventors addressed inU.S. patent application Ser. No. 11/104,103 the VOC emissions oforganofunctional silanes containing alkanedioxysilyl groups. The entirecontents of U.S. patent application Ser. Nos. 11/358,550; 11/358,818;11/358,681; 11/505,055; 11/505,166; 11/505,178; and 11/104,103 areincorporated by reference herein.

However, there is still a need to further improve the couplingperformance of organofunctional silanes to impart better wear andreinforcing properties to elastomeric materials while maintaining lowVOC emissions from the filled elastomeric materials and elastomericarticles during their preparation and use.

SUMMARY OF THE INVENTION

In one embodiment, the present invention provides a filled elastomercomposition comprising:

-   a) at least one rubber component;-   b) at least one particulate filler; and,-   c) at least one mercaptofunctional silane    general Formula (1):

[HSG¹SiZ^(θ)Z^(β)]_(m)[HSG²SiZ^(β) ₃]_(n)[HSG³SiZ^(β)₂X]_(o)[[HSG⁴SiZ^(β)X₂]_(p)   (1)

wherein:

each occurrence of G¹, G², G³, and G⁴ is independently a hydrocarbylenegroup containing from 1 to 30 carbon atoms selected from the groupconsisting of divalent groups derived by substitution of a hydrogen onalkyl, alkenyl, aryl, or aralkyl or a substituted divalent heterocarboncontaining 2 to 30 carbon atoms and one or more etheric oxygen (—O—)and/or sulfur (—S—) atoms;

each occurrence of X is independently selected from the group consistingof —Cl, —Br, RO—, RC(═O)O—, R₂C═NO—, R₂NO—, —R, (HO)_(d-1)G⁵O—, whereineach R is independently selected from the group consisting of hydrogen,straight, cyclic or branched alkyl that can or can not containunsaturation, alkenyl groups, aryl groups, and aralkyl groups, whereineach R, other than hydrogen, contains from 1 to 18 carbon atoms, G⁵ isindependently a hydrocarbylene group of from 2 to 15 carbon atoms or adivalent heterocarbon group of from about 4 to about 15 carbon atomscontaining one or more etheric oxygen atoms;

each occurrence of Z^(β), which forms a bridging structure between twosilicon atoms, is [—OG⁵(OH)_(d-2)O—]_(0.5), wherein each occurrence ofG⁵ is independently selected form the group consisting of ahydrocarbylene group from 2 to 15 carbon atoms or a divalentheterocarbon group of from 4 to 15 carbon atoms containing one or moreetheric oxygen atoms;

each occurrence of Z^(θ), which forms a cyclic structure with a siliconatom, is independently given by —OG⁵(OH)_(d-2)O—, wherein G⁵ isindependently selected form the group consisting of a hydrocarbylenegroup of from 2 to 15 carbon atoms or a divalent heterocarbon group offrom 4 to 15 carbon atoms containing one or more etheric oxygen atoms;

each occurrence of subscripts d, m, n, o and p independently is aninteger wherein d is from 2 to 6 in a first embodiment, 2 or 3 in asecond embodiment and 2 in a third embodiment; m is 0 to 20; n is 0 to18; o is 0 to 20; and, p is 0 to 20, with the proviso that m+n+o+p isequal to or greater than 2.

In another embodiment, the present invention is directed to a processfor making a filled elastomer composition which comprises:

-   a) mixing:    -   (i) at least one rubber component,    -   (ii) at least one particulate filler, and    -   (iii) at least one mercaptofunctional silane of Formula (1),        supra;-   b) optionally mixing:    -   (iv) at least one curative and/or    -   (v) at least one accelerator and/or    -   (vi) at least one polyhydroxy-containing compound into the        composition resulting from step (a);-   c) optionally molding the composition resulting from step (b); and,-   d) optionally curing the composition resulting from step (b) and    step (c).

DETAILED DESCRIPTION OF THE INVENTION

The expression “organofunctional silane” as used herein shall beunderstood to mean a dimeric, oligomeric or polymeric silane possessingmercaptan functionality and silane dimers, oligomers and/or polymers inwhich adjacent silane units are bonded to each other through bridgeddialkoxysilane structures derived from polyhydroxy-containing compounds.

It will be understood that all ranges herein include all subrangestherebetween. It will also be understood that all listings of members ofa group can further comprise combinations of any two or more members ofthe group.

Mercaptofunctional silanes of general Formula (1) are prepared by theprocess which comprises reacting

a) at least one mercaptofunctional silane selected from the groupconsisting of general Formulae (2), (3), (4) and (5):

(HS)-G¹-(SiX₃)   (2)

(HS)-G²-(SiX₃)   (3)

(HS)-G³-(SiX₃)   (4)

(HS)-G⁴-(SiX₃)   (5)

wherein:

each occurrence of G¹, G², G³, and G⁴is independently a hydrocarbylenegroup containing from 1 to 30 carbon atoms derived by substitution of ahydrogen on alkyl, alkenyl, aryl, or aralkyl or a divalent heterocarbongroup containing 2 to 30 carbon atoms and one or more etheric oxygen(—O—) and/or sulfur (—S—) atoms;

each occurrence of X is independently selected from the group consistingof —Cl, —Br, RO—, RC(═O)O—, R₂C═NO—, R₂NO—, —R, wherein each R isindependently selected from the group consisting of hydrogen, straight,cyclic or branched alkyl that can or can not contain unsaturation,alkenyl groups, aryl groups, and aralkyl groups, wherein each R, otherthan hydrogen, contains from 1 to 18 carbon atoms, with the proviso thatat least one, and advantageously, two of X are hydrolyzable groups; with

b) one or more polyhydroxy-containing compounds of general Formula (6):

G⁴(OH)_(d)   (6)

wherein G⁴ is a hydrocarbyl group of from 2 to 15 carbon atoms or aheterocarbyl group of from 4 to 15 carbon atoms containing one or moreetheric oxygen atoms and d is an integer of from 2 to 6, undertranesterification reaction conditions, thereby producingmercaptofunctional silane (1).

In one particular embodiment of the invention, the silane reactants aretrialkoxysilanes represented by at least one of general Formulae (7) and(10):

(HS)-G¹-(SiOR)₃   (7)

(HS)-G²-(SiOR)₃   (8)

(HS)-G³-(SiOR)₃   (9)

(HS)-G⁴-(SiOR)₃   (10)

wherein:

each occurrence of G¹, G², G³, and G⁴ is independently a hydrocarbylenegroup containing from 1 to 12 carbon atoms derived by substitution of ahydrogen on alkyl, alkenyl, aryl, or aralkyl;

each R independently has one of the aforestated meanings and,advantageously, is a methyl, ethyl, propyl, isopropyl, n-butyl orsec-butyl group.

In one embodiment herein, in a silane dimer, oligomer, or polymer, eachsilane unit of the dimer, oligomer or polymer is bonded to an adjacentsilane unit through a bridging group resulting from the reaction of theselected silane monomer(s) with one or more polyhydroxy-containingcompounds of general Formula (11):

G⁵(OH)_(d)   (11)

wherein G⁵ is a hydrocarbyl group of from 2 to 15 carbon atoms or aheterocarbyl group of from 4 to 15 carbon atoms containing one or moreetheric oxygen atoms and d is an integer of from 2 to 6, morespecifically from 2 to 4, and still more specifically 2.

In one embodiment herein, polyhydroxy-containing compound of Formula(11) is a diol (glycol) of at least one of the general Formulae (12) and(13):

HO(R⁰CR⁰)_(f)OH   (12)

HO(CR₀ ₂CR⁰ ₂O)_(e)H   (13)

wherein R⁰ is independently given by one of the members listed above forR, f is 2 to 15 and e is 2 to 7.

Some representative non-limiting examples of such diols are HOCH₂CH₂OH,HOCH₂CH₂CH₂OH, HOCH₂CH₂CH₂CH₂OH, HOCH₂CH(CH₃)CH₂OH,(CH₃)₂C(OH)CH₂CH(OH)CH₃, CH₃CH(OH)CH₂CH₂OH, diols possessing an ethericoxygen-containing group such as HOCH₂CH₂OCH₂CH₂OH,HOCH₂CH₂CH₂OCH₂—CH₂CH₂OH, HOCH₂CH(CH₃)OCH₂CH(CH₃)OH and diols possessinga polyether backbone such HOCH₂CH₂OCH₂CH₂OCH₂CH₂OH, a diol of Formula(12) wherein R⁰ is hydrogen or methyl and e is 3 to 7.

In another embodiment herein, polyhydroxy-containing compound of Formula(11) possesses higher hydroxyl functionality, such as triols andtetrols, of general Formula (14):

G⁴(OH)_(d)   (14)

wherein G⁵ is a is a substituted hydrocarbyl group of from 2 to 15carbon atoms or a substituted heterocarbon of from 4 to 15 carbon atomscontaining one or more etheric oxygen atoms; and, d is an integer offrom 3 to 6.

Some non-limiting examples of higher hydroxyl functionality compounds(14) include glycerol, trimethylolethane, trimethylolpropane,1,2,4-butanetriol, 1,2,6-hexanetriol, pentaerythritol,dipentaerythritol, tripentaerythritol, mannitol, galacticol, sorbitol,and combinations thereof. Mixtures of polyhydroxy-containing compoundsof Formulae (11)-(14) can also be used herein.

In one embodiment of the general preparative process described above, atleast one mercaptofunctional trialkoxysilane selected from amongstFormulae (7), (8), (9) and/or (10) is transesterified with at least onediol of Formula (11), optionally, in the presence of atransesterification catalyst such as para-toluenesulfonic acid, toprovide mercaptofunctional silane of Formula (1).

In one application of the foregoing embodiment of the generalpreparative process, at least one mercaptotrialkoxysilane of Formulae(7), (8), (9) and (10) wherein:

each occurrence of G¹, G², G³, and G⁴ is independently a hydrocarbylenegroup containing from 1 to 30 carbon atoms derived by substitution of ahydrogen on alkyl, alkenyl, aryl or aralkyl, more specifically astraight or branched chain alkylene group of from 1 to 6 carbon atoms,even more specifically from 1 to 3 carbon atoms, and still morespecifically 3 carbon atoms;

each R is independently selected from the group consisting of straight,cyclic and branched alkyl, alkenyl, aryl and aralkyl containing up to 18carbon atoms; is transesterified with at least one diol of Formula (12),wherein:

each occurrence of R⁰ and f is independently given by one of the memberslisted above for R and hydrogen, and f is 2 to 15, more specifically,each occurrence of R⁰ is independently selected from the groupconsisting of hydrogen and a straight or branched chain alkyl group offrom 1 to 6 carbon atoms and f is an integer from about 2 to about 6,and even more specifically, each occurrence of R⁰ is independentlyselected from the group consisting of a hydrogen and a straight orbranched chain alkyl group from 1 to 3 carbon atoms and f is an integerof from 2 to 4, and more specifically, each occurrence of R⁰ isindependently selected from the group consisting of hydrogen and astraight chain alkyl group of 1 or 2 carbon atoms and with the provisothat at least one R⁰ is an alkyl group and f is an integer of 2 or 3,optionally in the presence of transesterification catalyst such as thenon-limiting example of para-toluenesulfonic acid, to provide amercaptofunctional silane of Formula (1):

[HSG¹SiZ^(θ)Z^(β)]_(m)[HSG²SiZ^(β) ₃]_(n)[HSG³SiZ^(β)₂X]_(o)[[HSG⁴SiZ^(β)X₂]_(p)   (1)

wherein:

each occurrence of G¹, G², G³ and G⁴ is independently a hydrocarbylenegroup containing from 1 to 30 carbon atoms derived by substitution of ahydrogen on alkyl, alkenyl, aryl, or aralkyl, more specifically astraight or branched chain alkylene group of from 1 to 6 carbon atoms,even more specifically from 1 to 3 carbon atoms and still morespecifically 3 carbon atoms;

each occurrence of Z^(β), which forms a bridging structure between twosilicon atoms, is independently [—O(R⁰CR⁰)_(f)O—]_(0.5), wherein eachoccurrence of R⁰ is independently given by one of the members listedabove for R, and f is from 2 to 15, and more specifically eachoccurrence of R⁰ is independently selected from the group consisting ofhydrogen and a straight or branched chain alkyl group of from 1 to 6carbon atoms and f is an integer from 2 to 6, and even morespecifically, each occurrence of R⁰ is independently selected from thegroup consisting of hydrogen and a straight or branched chain alkylgroup of from about 1 to 3 carbon atoms and f is an integer of from 2 to4, and most specifically, each occurrence of R⁰ is independentlyselected from the group consisting of hydrogen and a straight chainalkyl group 1 or 2 carbon atoms and with the proviso that at least oneR⁰ is an alkyl group and f is an integer of 2 or 3;

each occurrence of Z^(θ), which forms a cyclic structure with a siliconatom, is independently —O(R⁰CR⁰)_(f)O—, wherein each occurrence of R⁰ isindependently given by one of the members listed above for R, and f is 2to 15, and more specifically each occurrence of R⁰ is independentlyselected from the group consisting of hydrogen and a straight orbranched chain alkyl group of from 1 to 6 carbon atoms and f is aninteger of from 2 to 6, and even more specifically, each occurrence ofR⁰ is independently selected from the group consisting of hydrogen and astraight or branched chain alkyl group from 1 to 3 carbon atoms and f isan integer of from 2 to 4, and most specifically, each occurrence of R⁰is independently selected from the group consisting of hydrogen and astraight chain alkyl group of 1 or 2 carbon atoms and with the provisothat at least one R⁰ is an alkyl group and f is an integer of 2 or 3;

each occurrence of X is independently —OR, wherein each occurrence of Ris independently selected from the group consisting of straight, cyclicand branched alkyl, alkenyl, aryl and aralkyl containing up to 18 carbonatoms; and,

each occurrence of m, n, o, and p independently is an integer wherein mis from 0 to 20, more specifically from 0 to 5 and even morespecifically from 0 to 2; n is specifically from 0 to 18, morespecifically from 0 to 4, and even more specifically from 0 to 2 andstill more specifically 1 or 2; o is specifically from 0 to 20, morespecifically from 0 to 5, even more specifically from 0 to 2 and stillmore specifically 1 or 2; p is specifically from 0 to about 20, morespecifically from 0 to 5 and even more specifically from 0 to 2; withthe proviso that m+n+o+p is equal to or greater than 2.

In another specific embodiment, each occurrence of m, n, o and pindependently is an integer wherein m is from 0 to 2, n is from 0 to 2,o is from 0 to 2 and p is 0 to 2, more specifically, m is from 2 to 4, nis from 0 to 2, o is from 0 to 2 and p is 0 and even more specifically,m is 0, n is from 0 to 2, o is from 0 to 2 and p is 2 to 4, and stillmore specifically, m is 2, n is 0, o is 0 and p is 0, and still morespecifically, m is 0, n is 0, o is 0 and p is 2.

In another specific embodiment, each occurrence of G¹, G², G³ and G⁴independently is a divalent straight or branched chain alkylene group offrom 1 to 6 carbon atoms, more specifically from 1 to 4 carbon atoms andstill more specifically of 2 or 3 carbon atoms.

In another embodiment, G¹, G², G³ and G⁴ are the same hydrocarbylenegroup containing from 1 to 30 carbon atoms, more specifically the samestraight or branched chain alkylene group of from about 1 to 6 carbonatoms, more specifically the same straight or branched chain alkylenegroup of from 1 to 4 carbon atoms and still more specifically the samestraight chain alkylene group of 2 or 3 carbon atoms.

In another embodiment, at least one G¹, G², G³ and G⁴ group is differentfrom the other G¹, G², G³ and G⁴ group and each occurrence of G¹, G², G³and G⁴ independently is a hydrocarbylene group containing from 1 to 30carbon atoms, more specifically a straight or branched chain alkylenegroup of from 1 to 6 carbon atoms, still more specifically a straight orbranched chain alkylene group of from 1 to 4 carbon atoms and yet stillmore specifically a straight chain alkylene group of 2 or 3 carbonatoms.

Reaction conditions for preparing mercaptofunctional silanes of Formula(1) and their mixtures are fairly broad and include molar ratios ofsilane(s), determined by adding the individual molar contribution ofsilanes of Formulae (2), (3), (4) and/or (5), and polyhydroxy-containingcompound(s) of Formula (6), of from about 0.3 to about 3 moles ofcompound of Formula (6) per mole of silyl group, more specifically fromabout 0.5 to about 2 moles of compound of Formula (6) per mole of silylgroup, and still more specifically from about 1 to about 1.5 moles ofFormula (6) per mole of silyl group, at a temperature of from about 0°C. to about 150° C., a pressure of from about 0.1 to about 2,000 mmHg,and in the optional presence of catalyst and/or solvent.

In another specific embodiment herein, there is providedmercaptofunctional and cyclic and/or bridging dialkoxy silane of Formula(1):

[HSG¹SiZ^(θ)Z^(β)]_(m)[HSG²SiZ^(β) ₃]_(n)[HSG³SiZ^(β)₂X]_(o)[[HSG⁴SiZ^(β)X₂]_(p)   (1)

wherein:

each occurrence of G¹, G², G³ and G⁴ is independently a group derived bysubstitution of hydrogen on alkyl, alkenyl, aryl, or aralkyl having from1 to about 30 carbon atoms;

each occurrence of X is independently selected from the group consistingof —Cl, —Br, RO—, RC(═O)O—, R₂C═NO—, R₂NO—, R₂N—, —R, (HO)_(d-1)G⁵O—,HO(CR⁰ ₂)_(f)O—, and HO(CR⁰ ₂CR⁰ ₂O)_(e)—, wherein each R isindependently selected from the group consisting of hydrogen, straight,cyclic or branched alkyl that can, or does not, contain unsaturation,alkenyl groups, aryl groups, and aralkyl groups, wherein each R, otherthan hydrogen, contains from 1 to 18 carbon atoms, G⁵ is independently ahydrocarbylene group of from 2 to 15 carbon atoms or a divalentheterocarbon group of from 4 to 15 carbon atoms containing one or moreetheric oxygen atoms, R⁰ is independently given by one of the memberslisted for R, f is 2 to 15 and e is 2 to 7;

each occurrence of Z^(β), which forms a bridging structure between twosilicon atoms, is independently selected from the group consisting of,[—OG⁵(OH)_(d-2)O—]_(0.5), [—O(CR⁰ ₂CR⁰ ₂O)_(e)—]_(0.5) and[—O(R⁰CR⁰)_(f)O—]_(0.5), wherein each occurrence of R⁰ is independentlygiven by one of the members listed above for R; and, each occurrence ofG⁵ is independently selected form the group consisting of a substitutedhydrocarbon group of from 2 to 15 carbon atoms or a substitutedheterocarbon of from 4 to 15 carbon atoms and containing one or moreetheric oxygen atoms;

each occurrence of Z^(θ), which forms a cyclic structure with a siliconatom, is independently given by —OG⁵(OH)_(d-2)O—, —O(CR⁰ ₂CR⁰ ₂O)_(e)—and —O(R⁰CR⁰)_(f)O— wherein each occurrence of R⁰ is independently givenby one of the members listed above for R;

each occurrence of the subscripts, d, e, f, m, n, o and p isindependently an integer wherein d is from 2 to 6, more specificallyfrom 2 to 4 and still more specifically 2; e is from 2 to 7, morespecifically from 2 to 4 and still more specifically 2; f is from about2 to 15, more specifically from 2 to 4 and still more specifically 3; mis from 0 to 20, more specifically from 0 to 5 and still morespecifically from 1 or 2; n is from 0 to 18, more specifically from 0 to4 and still more specifically from 1 or 2; o is from 0 to 20, andspecifically from 0 to 5, and still more specifically 1 to 2, and p isfrom 0 to 20, more specifically 0 to 5, and still more specifically from0 to 2, with the proviso that m+n+o+p is equal to or greater than 2 andwith the additional proviso that each of the above mercaptofunctionalsilanes of Formula (1) contains at least one hydrolysable group, Z^(β)orZ^(θ).

It will be appreciated that the structure, [—OG⁴(OH)_(d-2)(O—)]_(0.5)can further react with a third or more silyl groups to form bridgingtrialkoxysilyl, tetraalkoxysilyl groups, and so on, and are representedby [—OG⁵(OH)_(d-3)(O—)₂]_(1/3), [—OG⁵(OH)_(d-4)(O—)₃]_(1/4), and so on.

In accordance with another embodiment herein, a process for thepreparation of a mercaptofunctional silane containing cyclic and/orbridging dialkoxysilyl groups is provided which comprises blending atleast one mercaptofunctional silane selected from the group consistingof Formulae (2), (3), (4) and (5):

(HS)-G¹-(SiX₃)   (2)

(HS)-G²-(SiX₃)   (3)

(HS)-G³-(SiX₃)   (4)

(HS)-G⁴-(SiX₃)   (5)

wherein each occurrence of G¹, G², G³, G⁴ and X has one of theaforestated meanings and with the proviso that at least one of X is ahydrolyzable group; and transesterifying the mixture with one or morepolyhydroxy-containing compounds of general Formula (6):

G⁵(OH)_(d)   (6)

wherein each occurrence of G⁵ and d have one of the aforestatedmeanings, advantageously in the presence of a transesterificationcatalyst.

In another embodiment, a process for the preparation ofmercaptofunctional silane containing cyclic and/or bridging dialkoxysilyl groups is provided which comprises blending at least onemercaptofunctional silane selected from the group consisting of theFormulae (2), (3), (4) and (5):

(HS)-G¹-(SiX₃)   (2)

(HS)-G²-(SiX₃)   (3)

(HS)-G³-(SiX₃)   (4)

(HS)-G⁴-(SiX₃)   (5)

wherein each occurrence of G¹, G², G³, G⁴ and X has one of theaforestated meanings and with the proviso that at least one of X is ahydrolyzable group; and transesterifying the mixture with one or morediols of general Formulae (12) and (13):

HO(R⁰CR⁰)_(f)OH   (12)

HO(CR₀ ₂CR⁰ ₂O)_(e)H   (13)

wherein R⁰, e, and f have one of the aforestated meanings.

In one embodiment herein in connection with silanes of Formula (1), theterms “diol” and “difunctional alcohol” refer to any structure ofgeneral Formula (12):

HO(R⁰CR⁰)_(f)OH   (12)

wherein f and R⁰ are as defined herein. These structures includehydrocarbons in which two hydrogen atoms are replaced with —OH inaccordance with compounds of Formula (11), supra.

In another embodiment herein in connection with silanes of Formula (1),“dialkoxy” and “difunctional alkoxy” refer to hydrocarbon-based diols inwhich the two OH hydrogen atoms have been removed to give divalentradicals, and whose structures are represented by general Formula (14):

—O(R⁰CR⁰)_(f)O—  (14)

wherein f and R⁰ are as defined herein.

In yet another embodiment herein in connection with silanes of Formula(1), “cyclic dialkoxy” refers to a silane or group in which cyclizationis about a silicon atom by two oxygen atoms each of which is attached toa common divalent hydrocarbon group such as is commonly the case withdiols. In one embodiment cyclic, dialkoxy groups herein are representedby Z^(θ) which is important in the formation of the cyclic structure. Inyet another embodiment, R⁰ groups that are more sterically hindered thanhydrogen promote the formation of cyclic structures. In yet a furthermore embodiment the formation of cyclic structures is also promoted whenthe value of f in the diol of Formula (12) is 2 or 3, and morespecifically 3.

In yet a further embodiment herein in connection with silanes of Formula(1), “bridging dialkoxy” refers to a silane or group in which twodifferent silicon atoms are each bound to one oxygen atom, which in turnis bound to a common divalent hydrocarbon group such as is commonlyfound in diols. Bridging dialkoxy groups herein are represented byZ^(β).

In yet still a further embodiment herein in connection with silanes ofFormula (1), “hydroxyalkoxy” refers to a silane or group in which one OHhydrogen atom has been removed to provide a monovalent radical, andwhose structures are represented by general Formulae (15), (16) and(17):

(HO)_(d-1)G⁵O—  (15)

HO(R⁰CR⁰)_(f)O—  (16)

HO(CR⁰ ₂CR⁰ ₂O)_(e)—  (17)

wherein G⁵, e, f and R⁰ are defined above. Hydroxyalkoxy groups hereinare represented by X.

In yet another embodiment herein in connection with silanes of Formula(1), the term “hydrocarbon based diols” refers to diols that contain twoOH groups as part of a hydrocarbon structure. In another embodiment,absent from these hydrocarbon based diols are heteroatoms (other thanthe oxygens in the OH groups), in particular ether groups. In oneembodiment, hydrocarbon diols that contain heteroatoms, such as oxygen,are represented by Formula (13):

HO(CR⁰ ₂CR⁰ ₂O)_(e)—H   (13).

In another embodiment, these diols are not as likely to form cyclicstructures with the silyl group because of the size of the ring being 8atoms or larger, which are less likely to form than rings that contain 5or 6 atoms.

Structures of Formula (12) will be referred to herein as either “theappropriate diol” or “glycol” prefixed by the particular hydrocarbongroup associated with the two OH groups. In one specific embodiment,some non-limiting examples of Formula (12) include neopentylglycol,1,3-butanediol, 2-methyl-1,3-propanediol and 2-methyl-2,4-pentanediol.

Structures of Formula (14) will be referred to herein as the appropriatedialkoxy, prefixed by the particular hydrocarbon group associated withthe two OH groups, for example, the diols neopentylglycol,1,3-butanediol and 2-methyl-2,4-pentanediol correspond herein to thedialkoxy groups neopentylglycoxy, 1,3-butanedialkoxy,2-methyl-1,3-propanedialkoxy and 2-methyl-2,4-pentanedialkoxy,respectively.

In connection with Z^(β), the notations [—OG⁵(OH)_(d-2)O—]_(0.5),[—O(R⁰CR⁰)_(f)O—]_(0.5), and [—O(CR⁰ ₂CR⁰ ₂O)_(e)—]_(0.5) refer toone-half of a bridging dialkoxy group which can connect to differentsilyl groups present in the mercaptofunctional silanes of Formula (1).These notations are used in conjunction with a silicon atom and they aretaken herein to mean that one-half of a dialkoxy group is bound to theassociated silicon atom. It is understood that the other half of thedialkoxy group is bound to a silicon atom that occurs somewhere else inthe overall molecular structure being described. Thus, in oneembodiment, the [—OG⁵(OH)_(d-2)O—]_(0.5), [—O(R⁰CR⁰)_(f)O—]_(0.5) and[—O(CR⁰ ₂CR⁰ ₂O)_(e)—]_(0.5) dialkoxy groups mediate the chemical bondsthat hold two separate silicon atoms together, whether these two siliconatoms occur intermolecularly or intramolecularly. In one embodiment, inthe case of [—O(R⁰CR⁰)_(f)O—]_(0.5) and [—O(CR⁰ ₂CR⁰ ₂O)_(e)]_(0.5), ifthe group (R⁰CR⁰)_(f) and (CR⁰ ₂CR⁰ ₂O)_(e) are unsymmetrical, eitherend of [—O(R⁰CR⁰)_(f)O—]_(0.5) and [—O(CR⁰ ₂CR⁰ ₂O)_(e)—]_(0.5) can bebound to either of the two silicon atoms required to complete thestructures of silanes of Formula (1).

In still a further embodiment herein in connection with silanes ofFormulae (1), (2), (3), (4), (5), (7), (8), (9), and (10), “alkyl”includes straight, branched and cyclic alkyl groups; “alkenyl” includesany straight, branched, or cyclic alkenyl group containing one or morecarbon-carbon double bond, where the point of substitution can be eitherat a carbon-carbon double bond or elsewhere in the group; “aryl”includes the non-limiting group of any aromatic hydrocarbon from whichone hydrogen atom has been removed; “aralkyl” includes, but is notlimited to, any of the aforementioned alkyl groups in which one or morehydrogen atoms have been substituted by the same number of like and/ordifferent aryl (as defined herein) substituents. Specific examples ofalkyls include, but are not limited to, methyl, ethyl, propyl andisobutyl. Specific examples of alkenyls include, but are not limited to,vinyl, propenyl, allyl, methallyl, ethylidenyl norbomane, ethylidenenorbomyl, ethylidenyl norbomene and ethylidene norbomenyl. Specificexamples of aryls include, but are not limited to, tolyl, xylyl, phenyland naphthalenyl. Specific examples of aralkyls include, but are notlimited to, benzyl and phenethyl.

In another embodiment herein, in connection with silanes of Formula (1),(2), (3), (4), (5), (7), (8), (9), and (10), “cyclic alkyl”, “cyclicalkenyl”, also include bicyclic, tricyclic, and higher cyclicstructures, as well as the aforementioned cyclic structures furthersubstituted with alkyl, alkenyl, groups. Representative examples of“cyclic alkyl”, “cyclic alkenyl”, include, but are not limited to,norbomyl, norbomenyl, ethylnorbomyl, ethylnorbomenyl, ethylcyclohexyl,ethylcyclohexenyl, cyclohexylcyclohexyl and cyclododecatrienyl.

In another embodiment herein, the silane is one described by Formula (1)in which G¹, G², G³and G⁴ is independently a divalent group derived bysubstitution of C₁-C₁₂ alkyl; X is —R and/or —OR, wherein R is methyl,ethyl and/or —O(R⁰CR⁰)_(f)OH; Z^(β) is [—O(R⁰CR⁰)_(f)O—]_(0.5) and Z^(θ)is —O(R⁰CR⁰)_(f)O— wherein R⁰ is hydrogen or methyl, f is 2 or 3 and m,n, o and p are 0 to 2, with the proviso that m+n+o+p is equal to orgreater than 2. In still another embodiment herein, the silane is onedescribed by Formula (1) in which G¹, G², G³and G⁴ is independently adivalent group derived by substitution of C₃-C₆ straight chain alkyl; Xis —OR, wherein R is ethyl or —O(R⁰CR⁰)_(f)OH; Z^(β) is[—O(R⁰CR⁰)_(f)O—]_(0.5) and Z^(θ) is —O(R⁰CR⁰)_(f)O— wherein R⁰ ishydrogen or methyl, f is 2 or 3 and m, n, o and p are 0 to 2, with theproviso that m+n+o+p is equal to or greater than 2.

Some representative examples of G¹, G², G³ and G⁴ include, but are notlimited to those selected from the group consisting of -branchedalkylene groups of 1 to 30 carbon atoms and include the non-limitingexamples such as —CH₂(CH₂)₄CH(CH₂CH₃)CH₂—, —CH₂CH₂CH(CH₂CH₃)CH₂—,—CH₂CH(CH₃)CH₂—, —CH₂CH₂CH(CH₃)CH₂—, and —CH₂(CH₂)₄CH(CH₃)CH₂—;diethylene cyclohexane; phenylene; any of the structures derivable fromdivinylbenzene, such as the non-limiting examples of—CH₂CH₂(C₆H₄)CH₂CH₂— and —CH₂CH₂(C₆H₄)CH(CH₃)—, where the notation C₆H₄denotes a disubstituted benzene ring; any of the structures derivablefrom dipropenylbenzene, such as the non-limiting examples of—CH₂CH(CH₃)(C₆H₄)CH(CH₃)CH₂—, where the notation C₆H₄ denotes adisubstituted benzene ring; any of the structures derivable frompiperylene, such as the non-limiting examples of —CH₂CH₂CH₂CH(CH₃)—,—CH₂CH₂CH(CH₂CH₃)—, and —CH₂CH(CH₂CH₂CH₃)—; any of the isomers of—CH₂CH₂-norbomyl-; any of the monounsaturated structures derivable frommyrcene containing a trisubstituted C═C, such as the non-limitingexamples of —CH₂CH[CH₂CH₂CH═C(CH₃)₂]CH₂CH₂—,—CH₂CH[CH₂CH₂CH═C(CH₃)₂]CH(CH₃)—, —CH₂C[CH₂CH₂CH═C(CH₃)₂](CH₂CH₃)—,—CH₂CH₂CH[CH₂CH₂CH═C(CH₃)₂]CH₂—, —CH₂CH₂(C—)(CH₃)[CH₂CH₂CH═C(CH₃)₂], and—CH₂CH[CH(CH₃)[CH₂CH₂CH═C(CH₃)₂]]—; and any of the monounsaturatedstructures derivable from myrcene lacking a trisubstituted C═C, such asthe non-limiting examples of —CH₂CH(CH═CH₂)CH₂CH₂CH₂C(CH₃)₂—,—CH₂CH(CH═CH₂)CH₂CH₂CH[CH(CH₃)₂]—, —CH₂C(═CH—CH₃)CH₂CH₂CH₂C(CH₃)₂—,—CH₂C(═CH—CH₃)CH₂CH₂CH[CH(CH₃)₂]—, —CH₂CH₂C(═CH₂)CH₂CH₂CH₂C(CH₃)₂—,—CH₂CH₂C(═CH₂)CH₂CH₂CH[CH(CH₃)₂]—, —CH₂CH═C(CH₃)₂CH₂CH₂CH₂C(CH₃)₂— and—CH₂CH═C(CH₃)₂CH₂CH₂CH[CH(CH₃)₂]; —(CH₂)_(g)— wherein g is an integer offrom 1 to 30, which represent terminal straight-chain alkyls furthersubstituted terminally at the other end, such as the non-limitingexamples of —CH₂—, —CH₂CH₂—, —CH₂CH₂CH₂—, and—CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂—; yheir beta-substituted analogs, such as—CH₂(CH₂)_(i)CH(CH₃)—, where i is preferably 0 to 16; methyl substitutedalkylene groups such as the non-limiting examples of—CH₂CH₂-methylcyclohexyl-, —CH₂CH₂C(CH₃)₂CH₂—, —CH₂CH(CH₃)CH₂—; any ofthe structures derivable from isoprene, such as —CH₂CH(CH₃)CH₂CH₂—,—CH₂CH(CH₃)CH(CH₃)—, —CH₂C(CH₃)(CH₂CH₃)—, —CH₂CH₂CH(CH₃)CH₂—,—CH₂CH₂C(CH₃)₂— and —CH₂CH[CH(CH₃)₂]—; any structure derivable frommethallyl chloride; any of the structures derivable from butadiene, suchas the non-limiting examples of —CH₂CH₂CH₂CH₂—, —CH₂CH₂CH(CH₃)—, and—CH₂CH(CH₂CH₃)—; and, any of the diradicals obtainable from norbomane,cyclohexane, or cyclopentane, by loss of two hydrogen atoms.

In yet another embodiment herein, G^(1,) G², G³ and G⁴ G^(1,) G², G³ andG⁴ is —CH₂CH₂CH₂—, X is —OCH₂CH(CH₃)CH₂OH and Z^(β) is[—OCH₂CH(CH₃)CH₂O—]_(0.5) and and Z^(θ) is —OCH₂CH(CH₃)CH₂O—.

In yet a further embodiment, some representative non-limiting examplesof R and R⁰ groups are hydrogen, branched and straight-chain alkyls of 1to 18 carbon atoms or more, such as the non-limiting examples of methyl,ethyl, propyl, isopropyl, butyl, octenyl, cyclohexyl, phenyl, benzyl,tolyl and allyl.

In one embodiment, R groups are selected from C₁ to C₄ alkyls andhydrogen and R⁰ groups are selected from hydrogen, methyl, ethyl andpropyl.

In one other embodiment, some specific non-limiting examples of X aremethoxy, ethoxy, isobutoxy, propoxy, isopropoxy, acetoxy, oximato,monovalent hydroxyalkoxy groups derived from diols, —O(R⁰CR⁰)_(f)OHwhere R⁰ and f is defined as herein, such as the non-limiting examplesof 2-hydroxyethoxy, 2-hydroxypropoxy, 3-hydroxy-2,2-dimethylpropoxy,3-hydroxypropoxy, 3-hydroxy-2-methylpropoxy, 3-hydroxybutoxy,4-hydroxy-2-methylpent-2-oxy, and 4-hydoxybut-1-oxy and monovalent etheralkoxy groups of general Formulae (18), (19), and (20):

(R¹O)_(d-1)G⁵O—  (18)

R¹O(R⁰CR⁰)_(f)O—  (19)

R¹O(CR₀ ₂CR⁰ ₂O)_(e)—  (20)

wherein R¹ is independently selected from the group consisting ofstraight, cyclic or branched alkyl groups, alkenyl groups, aryl groupsand aralkyl groups that contain from 1 to 18 carbon atoms; and R⁰, G⁵, eand f are defined as herein. In one embodiment X can also be amonovalent alkyl group, such as the non-limiting examples of methyl andethyl.

In a specific embodiment, X is one of the non-limiting examples ofmethoxy, ethoxy, acetoxy, methyl, ethyl, 2-hydroxyethoxy,2-hydroxypropoxy, 3-hydroxy-2,2-dimethylpropoxy, 3-hydroxypropoxy,3-hydroxy-2-methylpropoxy, 3-hydroxybutoxy,4-hydroxy-2-methylpent-2-oxy, and 4-hydoxybut-1-oxy.

In one embodiment, some specific non-limiting examples of Z^(β) andZ^(θ) are the divalent alkoxy groups derived from diols such as ethyleneglycol, propylene glycol, neopentyl glycol, 1,3-propanediol,2-methyl-1,3-propanediol, 1,3-butanediol, 2-methyl-2,4-pentanediol,1,4-butanediol, cyclohexane dimethanol and pinacol. In anotherembodiment, some more specific non-limiting examples of Z^(β) and Z^(θ)are divalent alkoxy groups derived from ethylene glycol, propyleneglycol, neopentyl glycol, 1,3-propanediol, 2-methyl-1,3-propanediol,1,3-butanediol and 2-methyl-2,4-pentanediol.

In one specific embodiment herein, Z^(β) and Z^(θ) are divalent alkoxygroups derived from 1,3-propanediol, 2-methyl-1,3-propanediol,1,3-butanediol, and 2-methyl-2,4-pentanediol and combinations thereof.In one embodiment, the cyclic dialkoxy content of the silanes hereinshould be kept sufficiently high relative to the total dialkoxy contentpresent to prevent excessive crosslinking, which would lead togellation. In one embodiment herein, the cyclic dialkoxy silyl contentof the silanes can be from about 10 to about 100 mole percent of thetotal concentration of silyl groups, specifically from about 25 to about90 mole percent of the total concentration of silyl groups and morespecifically from about 50 to about 70 mole percent of the totalconcentration of silyl groups. In another embodiment herein, excessivecrosslinking can also be avoided if X in the structure of Formula (1) islarge, such as for example, is the case when o and p are from about 1 toabout 5 and/or when the number of fragments, [HSG²Z^(β) ₃], in thestructure of Formula (1) is low, specifically, when o is 0 and 1.

In yet a further embodiment, some representative non-limiting examplesof the mercaptofunctional silanes herein, such as those that containcyclic and/or bridging dialkoxysilyl groups and mercapto groups include,but are not limited to,3-(2-{3-[2-(3-mercapto-propyl)-5-methyl-[1,3,2]dioxasilinan-2-yloxy]-2-methyl-propoxy}-5-methyl-[1,3,2]dioxasilinan-2-yl)-propane-1-thiol;3-(2-{3-[2-(3-mercapto-propy)-4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yloxy]-2-methyl-propoxy}-4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yl)-propane-thiol;3-(2-{3-[2-(3-mercapto-propyl)-4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yloxy]-1,1-dimethyl-butoxy}-4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yl)-propane-1-thiol;3-({3-[2-mercapto-propyl)-5-methyl-[1,3,2]dioxasilinan-yloxy]-2-methyl-propoxy}-bis-[3-hydroxy-2-methyl-propoxy]-silanyl)-propane-1-thiol;3-[{3-[{3-bis-(3-hydroxy-2-methyl-propyl)-(3-mercapto-propyl)-silanyloxy]-1-methyl-propoxy}-(3-hydroxy-2-methyl-propoxy)-(3-mercapto-propyl)-silanyloxy]-2-methyl-propan-1-ol;3-[[3-((3-hydroxy-3-methyl-propoxy)-3-mercapto-propyl)-{3-[2-(3-mercapto-propyl)-5-methyl-[1,3,2]dioxasilinan-2-yloxy]-1-methyl-propoxy}-silanyloxy)-2-methyl-propoxy-(3-hydroxy-2-methyl-propoxy)-3-mercapto-propyl)-silanyl]-2-methylpropan-1-ol;3-(2-{3-[2-(3-mercapto-butyl)-[1,3,2]dioxasilinan-2-yloxy]-propoxy}-[1,3,2]dioxasilinan-2-yl)-butane-1-thiol;3-(2-{3-[2-(3-mercapto-phenyl)-4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yloxy]-2-methyl-propoxy}-4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yl)-3-benzene-thiol;3-(2-{3-[2-(3-mercapto-cyclohexyl)-4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yloxy]-1,1-dimethyl-butoxy}-4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yl)-cyclohexane-1-thiol;3-({3-[2-mercapto-methyl)-5-methyl-[1,3,2]dioxasilinan-2-yloxy]-2-methyl-propoxy}-diethoxy]-silanyl)-methane-1-thiol;3-[{3-[{3-bis-(3-hydroxy-2,2-dimethyl-propyl)-(3-mercapto-propyl)-silanyloxy]-2,2-dimethyl-propoxy}-(3-hydroxy-2,2-dimethyl-propoxy)-(3-mercapto-propyl)-silanyloxy]-2,2-dimethyl-propan-1-ol;3-[[3-((3-hydroxy-3-phenyl-propoxy)-3-mercapto-propyl)-{3-[2-(3-mercapto-propyl)-5-phenyl-[1,3,2]dioxasilinan-2-yloxy]-2-phenyl-1-propoxy}-silanyloxy)-2-phenyl-propoxy-(3-hydroxy-2-phenyl-propoxy)-3-mercapto-propyl)-silanyl]-2-phenylpropan-1-ol;3-[{3-[(methyl)-(3-hydroxy-2-methyl-propoxy)-(3-mercapto-propyl)-silanyloxy]-2-methyl-propoxy}-methyl)-(3-mercapto-propyl)-silanyloxy]-2-methyl-propan-1-ol,and combinations thereof.

Moreover, in one other embodiment herein, it is understood that thesesilane compositions can also contain mercaptofunctional andmonofunctional alkoxy groups. In a further embodiment herein,mercaptofunctional silanes containing only monofunctional alkoxy groupscan be used as reagents in the preparation of the silanes herein.However, it is understood in one embodiment that these monofunctionalalkoxy groups can contribute to VOC emissions during use if themonofunctional alcohols that are form upon hydrolysis of the silaneshave high vapor pressure at room temperature. In a further embodiment,some non-limiting examples of high boiling monofunctional alkoxy groups,are those such as the alkoxy groups whose structures are represented bygeneral Formula (20)

R¹O(CR⁰ ₂CR⁰ ₂O)_(e)—  (20)

wherein R⁰, R¹ and e are defined as herein. In another embodiment,moreover, it is understood that the partial hydrolyzates and/orcondensates of these cyclic and/or bridging mercaptofunctional silanes(i.e., cyclic and/or bridging dialkoxy mercaptofunctional and siloxanesand/or silanols) can also be encompassed by the silanes herein, in thatthese partial hydrolyzates and/or condensates will be a side product ofmost methods of manufacture of the silanes described herein or can occurupon storage, especially in humid conditions, or under conditions inwhich residual water remaining from their preparation is not completelyremoved subsequent to their preparation.

Furthermore in another specific embodiment, partial to substantialhydrolysis of silanes of Formula (1) will form silanes that containsiloxane bonds, i.e., Z^(β)═(—O—)_(0.5), and are encompassed by thesilanes described herein; and in a more specific embodiment they can bedeliberately prepared by incorporating the appropriate stoichiometry oran excess of water into the methods of preparation described herein forthe silanes. In one embodiment, silane structures herein encompassinghydrolyzates and siloxanes are described in the structures representedby Formula (1) wherein Z^(β)═(—O—)_(0.5) and/or X^(α)═OH are substantive(i.e., substantially larger than zero), for example, the ratio of(—O—)_(0.5) to [—OG⁵(OH)_(d-2)O—]_(0.5) is specifically from 1 to 99,more specifically from 1 to 20, and still more specifically from 1 to 5,and with the proviso that the silane of Formula (1) contains at leastone Z^(β) that is [—OG⁵(OH)_(d-2)O—]_(0.5) or at least one Z^(θ) that is—OG⁵(OH)_(d-2)O—. In one embodiment herein, the ratio of siloxanebridging group, (—O—)_(0.5), to dioxy bridging group,[—O(R⁰CR⁰)_(f)O—]_(0.5), is within a range of from about 0 to about 1.In another embodiment, the ratio is within a range of from about 0 toabout 0.2. In a further embodiment, the ratio is within a range of fromabout 0.05 to about 0.15.

In another embodiment herein, the mercaptofunctional silanes herein,including their mixtures, can be loaded on a particulate carrier such asporous polymer, carbon black, a siliceous material such as silica, andthe like, so that they are in solid form for addition to rubber in arubber compounding operation.

In a further embodiment herein, mercaptofunctional silanes of Formula(1) herein and mixtures thereof can be prepared by the generalpreparative process described as herein of which there are numerousspecific embodiments. Generally, in one embodiment, the process formaking one or a mixture of silanes of Formula (1) involve atransesterification reaction between one or more alkoxysilanes ofFormulae (2), (3), (4) and (5) and one or more polyhydroxy-containingcompounds of Formulae (6), (11), (12) and (13).

In one embodiment, the process for preparing mercaptofunctional silaneof Formula (1) comprises:

a) mixing at least one mercaptosilanes of general Formulae (2), (3), (4)and/or (5): wherein each occurrence of G¹, G², G¹, G⁴, and X are definedas herein, and with the proviso that at least one of X is a hydrolyzablegroup; and

b) transesterifying this mixture with at least one diol having thestructure G⁵(OH)_(d), HO(R⁰CR⁰)_(f)OH, or HO(CR⁰ ₂CR⁰ ₂O)_(e)—H,optionally in the presence of a transesterification catalyst; andremoving the X—H group that is formed; wherein each occurrence of G⁵,R⁰, d, e and f are defined as herein.

In one embodiment, the first reaction can be carried out by reacting amixture of mercaptofunctional alkoxy silane with a diol at a molar ratioof about 0.5 mole to about 3.0 moles of diol per 1 mole of silyl groupto be transesterified. In another embodiment, the ratio can range fromabout 1.0 to about 2.5 for a trialkoxysilyl group. In yet a furtherembodiment, the ratio can range from about 1.5 to about 2.0 for atrialkoxysilyl group. In one embodiment, the reaction can be carried outat a temperature ranging from about 0 to about 150° C., morespecifically from about 25° C. to about 100° C. and still morespecifically from about 60° C. to about 80° C., and all subrangestherebetween, while maintaining a pressure in the range of from about0.1 to about 2000 mm Hg absolute. In one embodiment, the temperature canrange from about 30° C. to about 90° C. and all subranges therebetween.In another embodiment, the pressure can range from about 1 to about 80mm Hg absolute. As those skilled in the art will recognize, in oneembodiment, excess diol can be utilized to increase reaction rate, butit is not necessary under these conditions as it can increase the cost.In another embodiment, the reaction can be carried out by slowly addingdiol to the mixture of the mercaptofunctional alkoxysilane at thedesired reaction temperature and vacuum. In another embodiment, as thelower boiling X—H group, such as monoalcohol, is formed, it can beremoved from the reaction mixture by a distillation cycle and removal ofthe mono alcohol helps drive the reaction to completion. In oneembodiment, the reactions optionally can be catalyzed using atransesterification catalyst. In yet a further embodiment, suitabletranesterification catalysts are strong protic acids whose pK_(a) arebelow 5.0, transition metal complexes such as complexes of tin, iron,titanium and other metal catalysts. In one embodiment, catalystssuitable for these reaction are disclosed in, “The Siloxane Bond,Physical Properties and Chemical Transformations”, M. G. Voronkov, V. P.Mileshkevich and Yu. A. Yuzhelevskii, Consultants Bureau, a division ofPlenum Publishing Company, New York (1978), Chapter 5 and isincorporated by reference herein in its entirety. In a furtherembodiment, strong bases are generally unsuitable as transesterificationcatalysts since they promote the reaction of the mercaptofunctionalgroup with the diol and result in the formation of sulfides. In oneembodiment, the acid or metal catalysts can be used at a range of fromabout 10 ppm to about 2 weight percent, specifically from about 20 ppmto about 1000 ppm, and more specifically of from about 100 ppm to about500 ppm.

In a further embodiment herein, the final mixture can optionally bebuffered after the reaction is complete. In one specific embodiment,buffering the mixture will neutralize the strong protic acids andthereby be less corrosive to metals and add to long-term productstability. In a still further specific embodiment, buffering can beconducted through methods and compounds known in the art.

In one specific embodiment, the products of the transesterification ofmercaptofunctional silane (2), (3), (4) and/or (5) can comprise aconsiderable fraction of monomeric material in addition to the formationof dimers and other cyclic and/or bridged oligomers as illustrated bylow viscosity reaction products. In one specific embodiment the fractionof monomeric material is from about 1 to about 99 mole percent, morespecifically from about 10 to about 50 mole percent, and still morespecifically from about 15 to about 25 mole percent.

In a further embodiment, the process for making the mercaptofunctionalsilane compositions herein can optionally employ an inert solvent. In aspecific embodiment, the solvent can serve as a diluent, carrier,stabilizer, refluxing aid or heating agent. In a more specificembodiment, generally, any inert solvent that does not enter into thereaction or adversely affect the preparative process can be used. In oneembodiment, the solvents are liquid under normal conditions and have aboiling point below about 150° C. In a more specific embodiment, somenon-limiting examples of suitable solvents include aromatic or aliphatichydrocarbon, ether, aprotic, or chlorinated hydrocarbon solvents such astoluene, xylene, hexane, butane, diethyl ether, dimethylformamide,dimethyl sulfoxide, carbon tetrachloride, methylene chloride, andcombinations thereof.

In one embodiment herein, the process of transesterifying themercaptoalkoxysilane with polyhydroxy-containing compound can beconducted continuously. In one more embodiment, in the case of acontinuous operation, the process comprises:

a) reacting, in a thin film reactor, a thin film reaction mediumcomprising a mixture of at least one silane of Formulae (2), (3), (4)and/or (5), with at least one polyhydroxy-containing compound of Formula(6) and, optionally, transesterification catalyst, to providemercaptofunctional silanes that contains a cyclic and/or bridgeddialkoxy group, and by-product monoalcohol;

b) vaporizing by-product monoalcohol from the thin film to drive thereaction;

c) optionally, recovering by-product monoalcohol by condensation;

d) recovering the organofunctional silane reaction product(s); and,

e) optionally, neutralizing the reaction medium to improve the storagestability of the mercapto functional silane product(s) therein.

In one embodiment herein, the molar ratio of polyhydroxy-containingcompound to the mixture of mercaptofunctional silanes used in thecontinuous thin film process will depend upon the number of alkoxygroups that are desired to be replaced with a polyhydroxy-containinggroup, such as the non-limiting example of a diol (glycol). In one morespecific embodiment, theoretically, a molar ratio of about 1.5 mole ofdiol of Formula (11) or (12) is required per mole of alkoxy-silyl groupto be transesterified to replace all of the mono alkoxy or otherhydrolysable X-groups. In another embodiment herein, a molar ratio offrom about 0.5 to about 1.0 moles of diol can be used per mole ofalkoxy-silyl group. In a further embodiment, and, in many cases,additional diol is desirable because in some cases only one of thehydroxyl groups of the diol reacts with the alkoxysilyl group. In oneembodiment these diols that react only once with a silyl group aredefined as X in Formulae (1). In a further embodiment, the diols,referred to herein as “hydroxyalkoxy”, reduce the viscosity and inhibitthe gelation of the silane. In a still further embodiment and as oneskilled in the art will readily recognize that excess diol can beutilized to increase reaction rates.

In one specific embodiment, the method of forming the film can be any ofthose known in the art. In a more specific embodiment, typical knowndevices include but are not limited to, falling film or wiped filmevaporators. In one specific embodiment, minimum film thickness and flowrates will depend on the minimum wetting rate for the film formingsurface. In another specific embodiment, maximum film thickness and flowrates will depend on the flooding point for the film and device. In astill further specific embodiment, the alcohol is vaporized from thefilm by heating the film, by reducing pressure over the film, or by acombination of both. In one embodiment, mild heating and reducedpressure are utilized to form the structures described herein. In yet afurther embodiment, optimal temperatures and pressures (partial vacuum)for running the processes described herein will depend upon the specificmercaptofunctional silane's alkoxy groups and the diol used in theprocess. In yet an even further embodiment, additionally if an optionalinert solvent is used in the process, that choice will affect theoptimal temperatures and pressures (partial vacuum) utilized. In onespecific embodiment, some non-limiting examples of such solvents includethose listed herein. In one embodiment herein, the by-product X—H, suchas a monofunctional alcohol, vaporized from the film is removed from thereactive distillation device by a standard partial vacuum-forming deviceand can be condensed, collected, and recycled as feed to otherprocesses. In one embodiment, the silane product is recovered bystandard means from the reactive distillation device as a liquid phase.In another embodiment, if an inert solvent has been used or ifadditional purification is necessary, the silane product can be fed toanother similar distillation device or distillation column to effectthat separation. In still another specific embodiment, optionally thetransesterified reaction products can be neutralized to improve productstorage.

In one more specific embodiment, if a protic catalyst is used to promotethe transesterification of the silanes with diol, it can be useful toneutralize the catalyst with a base to improve the product's stability;however, only a stoichiometric amount of base is required to neutralizethe protic catalyst; larger amounts of base will promote undesirableside reactions.

Further, in another embodiment, a free-flowing filler composition isprovided which comprises:

a) at least one particulate filler; and,

b) a mercaptofunctional silane composition comprising at the silane ofFormula (1):

[HSG¹SiZ^(θ)Z^(β)]_(m)[HSG²SiZ^(β) ₃]_(n)[HSG³SiZ^(β)₂X]_(o)[[HSG⁴SiZ^(β)X₂]_(p)   (1)

wherein:

each occurrence of G¹, G², G³, and G⁴ are independently a hydrocarbylenegroup containing from 1 to 30 carbon atoms derived by substitution of ahydrogen on alkyl, alkenyl, aryl, or aralkyl or a divalent heterocarboncontaining 2 to 30 carbon atoms and one or more etheric oxygen (—O—)and/or sulfur (—S—) atoms;

each occurrence of X is independently selected from the group consistingof —Cl, —Br, RO—, RC(═O)O—, R₂C═NO—, R₂NO—, —R, (HO)_(d-1)G⁵O—, whereineach R is independently selected from the group consisting of hydrogen,straight, cyclic or branched alkyl that can or can not containunsaturation, alkenyl groups, aryl groups, and aralkyl groups, whereineach R, other than hydrogen, contains from 1 to 18 carbon atoms, G⁵ isindependently a substituted hydrocarbylene group of from 2 to 15 carbonatoms or a substituted heterocarbon group of from 4 to 15 carbon atomsand containing one or more etheric oxygen atoms;

each occurrence of Z^(β), which forms a bridging structure between twosilicon atoms, is [—OG⁵(OH)_(d-2)O—]_(0.5), wherein each occurrence ofG⁵ is independently selected form the group consisting of a substitutedhydrocarbylene group of from 2 to 15 carbon atoms or a substitutedheterocarbon of from 4 to 15 carbon atoms and containing one or moreetheric oxygen atoms;

each occurrence of Z^(θ), which forms a cyclic structure with a siliconatom, is independently given by —OG⁵(OH)_(d-2)O—, wherein G⁵ isindependently selected form the group consisting of a hydrocarbylenegroup of from 2 to 15 carbon atoms or a divalent heterocarbon of from 4to 15 carbon atoms and containing one or more etheric oxygen atoms;

each occurrence of the subscripts, d, m, n, o, and p independently is aninteger wherein d is from 2 to 6, more specifically 2 or 3 and stillmore specifically 2; m is from 0 to 20; n is specifically from 0 to 18;o is from 0 to 20; p is from 0 to 20; with the proviso that m+n+o+p isequal to or greater than 2.

In another embodiment herein there is provided an article ofmanufacture, such as the non-limiting examples selected from the groupconsisting of tires, industrial goods, shoe soles, hoses, seals,gaskets, and cable jackets, of which at least one component is the curedrubber composition of the herein described rubber compositions. In oneembodiment, the silanes and/or silane mixtures herein offer a means forsignificantly reducing volatile organic compound (VOC) emissions duringrubber manufacture, increase the dispersion of the filler within therubber, and improving the coupling between the organic polymers andfillers.

In another embodiment herein the mercaptofunctional silane-basedcompositions herein are useful as coupling agents between elastomericresins (i.e., rubbers) and fillers. In one embodiment, themercaptofunctional silane compositions are unique in that the highefficiency of the mercaptan group can be utilized without thedetrimental side effects typically associated with the use ofmercaptosilanes, such as high processing viscosity, less than desirablefiller dispersion, premature curing (scorch), and odor. In yet anotherembodiment, these benefits are obtained because the mercaptan group ispart of a high boiling compound that liberates diol or higherpolyhydroxy-containing compound upon use. In still another embodiment,during this non-productive mixing step, the cyclic and/or bridgedalkoxysilyl groups can react with the filler. In one embodiment hereinmercaptosilane composition, free-flowing filler composition and rubbercomposition can be cured as described herein and/or using proceduresknown to those skilled in the art.

In another specific embodiment herein, the mercaptofunctionalsilane-based compositions herein provide significant advantages overtraditional coupling agents that have found extensive use in the rubberand tire industries. These traditional silanes usually contain in theirmolecular structures three alkoxy groups, e.g., ethoxy groups, on eachsilicon atom, which results in the release of up to three moles ofsimple monohydroxy alcohol, e.g., ethanol for each silane equivalentduring the rubber manufacturing process in which the silane couples tothe filler. The release of simple mono alcohols is a great disadvantagebecause they are flammable and therefore pose a threat of fire, andbecause they contribute so greatly to volatile organic compound (VOC)emissions and are therefore potentially harmful to the environment.

In one specific embodiment herein, utilizing any of the silanes and/orsilane mixtures disclosed herein can result in VOC emission that isreduced. In one embodiment, VOC emission from a product/compositioncomprising the silanes or silanes mixtures disclosed herein can be lessthan the VOC emission in an equivalent product/composition that does notcontain said silanes or silanes mixtures disclosed herein. In yet afurther embodiment, reduced VOC emission can comprise specifically lessthan about 30 weight percent of the weight of the mercaptofunctionalsilane, more specifically less than about 10 weight percent of themercaptofunctional silane and most specifically less than about 1 weightpercent of the mercaptofunctional silane. In one embodiment, the VOCemission are reduced because the resulting byproducts of hydrolysis areG⁵(OH)_(d), (HO)(CR⁰ ₂)_(f)OH and HO(CR⁰ ₂CR⁰ ₂O)_(e)OH, are required tohave a having a boiling point greater than 180° C. at atmosphericpressure.

In one embodiment herein, the mercaptofunctional silane-basedcompositions described herein eliminate or greatly mitigate theforegoing problems by reducing volatile monoalcohol emissions to onlyone, less than one, and even essentially zero, moles of monoalcohol persilane equivalent. In one specific embodiment, they accomplish thisbecause the silane alkoxy groups are replaced with polyhydroxy alcohols,e.g., diol derived bridging groups, and thus such polyhydroxy alcoholsare released during the rubber manufacture process in place of much, ornearly all, of the mono alcohol released. In yet a further specificembodiment, describing the advantages of the mercaptofunctional silanesherein with specific reference to those silanes that are prepared withdiols (such advantages being realizable with polyhydroxy-containingcompounds of higher hydroxyl functionality), e.g., having boiling pointsin excess of rubber processing temperatures, are not vaporized out ofthe rubber during the rubber manufacture process, as is the case, e.g.,with ethanol, but are retained by the rubber where they migrate to thesilica surface due to their high polarity and become hydrogen bonded tothe surfaces of siliceous fillers such as silicas. In anotherembodiment, the presence of diols on silica surfaces leads to furtheradvantages not obtainable with ethanol (due to its volatility andejection during the rubber compounding process) in the subsequent cureprocess, in which such presence prevents the silica surface from bindingthe curatives and thereby interfering with the cure. Traditional silanesnot based on diols require more curatives to counter losses due tosilica binding.

In another embodiment, the addition of hydrocarbon-based diols orpolyhydroxyl-containing compounds to the rubber compounding formulationprior to and/or concurrent with the addition of curatives is ofadvantage for the efficient utilization of the curatives, in particular,and polar substances, such as, but not limited to, amines, amides,sulfenamides, thiurams, and guanidines. In yet another embodiment,whether diols or the polyhydroxyl-containing compounds are exclusivelyadded in the form of di- or polyhydroxyl-derived silanes or as freediols or polyhydroxyl-containing compounds in combination with thesilane coupling agents, the polarity of the diols orpolyhydroxyl-containing compounds is of advantage to the rubbercompounding process. In one more embodiment, these polar substances tendto migrate to the filler surface due to dipole interactions with thefiller; which tends to make them unavailable within the organic polymermatrix, where their functions include dispersion of the free flowingfiller composition and acceleration, or retardation, of the curingreactions. In one embodiment, the hydrocarbon-based diols orpolyhydroxyl-containing compounds enhance the function of the curativesby interfering with their tendency to bind to the silica surface therebyforcing them into the rubber matrix to perform their function. Inanother embodiment herein, the hydrocarbon-based diols orpolyhydroxyl-containing compounds accomplish this by themselves beingvery polar, and thereby by themselves binding to the filler surface,leaving less room for the curatives to bind to filler. In a furtherspecific embodiment, the hydrocarbon-based diols thus act as curativedisplacing agents from the filler. In yet another specific embodiment,the short chain of the hydrocarbon-based diols orpolyhydroxyl-containing compounds further enhances their function by achelate effect. In one embodiment, the number of carbon atoms betweenthe dialkoxide groups of Z^(θ) and/or Z^(β) herein are important and aredefined by the divalent radical —O(R⁰CR⁰)_(f)O— and[—(R⁰CR⁰)_(f)O—]_(0.5), respectively, wherein each occurrence of f is 2or 3. In a more specific embodiment, these chains of two or three carbonatoms between the two OH groups of the diol promote the formation of 5-or 6-membered rings when both oxygen atoms bind to a common silicon atomof the silanes of Formulae (1). In an even more specific embodiment,this dual binding to a common center, known, and referred to herein asthe chelate effect, increases the amount of cyclic dialkoxysilyl groupand inhibits the formation of gel. In a further specific embodiment,after reactions with the silica in the rubber-compounding step, thediols that have been released have a high affinity to the filler becausethey can chelate with the metal or silicon atom on the filler surfacethereby enhancing their ability to prevent the binding of the curativesto the filler. In a further specific embodiment an important advantageof the silanes and/or silane mixtures described herein is that theby-products of the silane coupling process are themselves of utility inenhancing the rubber compounding process, the value of the resultingrubber compositions, and/or any articles of manufacture employing therubber compositions. In one embodiment, thus, the mercaptosilanescontaining a bridging and/or cyclic dialkoxy group enhance the ease andcompleteness of filler dispersion and retarding the reversal of thisprocess, namely, filler reagglomeration.

In one embodiment herein there is provided a rubber compositioncomprising (a) at least one rubber component, (b) at least oneparticulate filler and (c) at least one mercaptofunctional silane asdescribed herein.

In one embodiment, an important advantage of the silanes describedherein is that the by-products of the silane coupling process arethemselves of utility in enhancing the rubber compounding process, thevalue of the resulting rubber compositions, and/or any articles ofmanufacture employing the rubber compositions.

In one embodiment, at least one of the mercaptofunctional silanecoupling agents that contain cyclic and/or bridging dialkoxysilyl groupsis mixed with the organic polymer before, during, or after thecompounding of the filler into the organic polymer. In one embodiment,the silanes are added before or during the compounding of the fillerinto the organic polymer because these silanes facilitate and improvethe dispersion of the filler. In a more specific embodiment, the totalamount of silane present in the resulting rubber composition should beabout 0.05 to about 25 parts by weight per hundred parts by weight oforganic polymer (phr). In another embodiment, the amount ofmercaptofunctional silane present in the free flowing filler compositionis from about 0.1 to about 70 weight percent based on total weight offree flowing filler composition. In yet another embodiment, the amountof mercaptofunctional silane present in the free flowing fillercomposition is from about 0.5 to about 20 weight percent based on totalweight of free flowing filler composition. In one other embodiment theamount of filler in the free flowing filler composition is from about99.9 to about 30 weight percent based on total weight of free flowingfiller composition. In yet one other embodiment the amount of filler inthe free flowing filler composition is from about 99.5 to about 80weight percent based on total weight of free flowing filler composition.In another embodiment, the amount of silane present in the rubber isfrom about 0.2 to 10 phr. In yet another embodiment, the amount ofsilane present in the rubber is from about 3 to 8 phr. In oneembodiment, fillers can be used in quantities ranging specifically fromabout 5 to about 100 phr, more specifically from about 25 to about 80phr and most specifically from about 50 to about 70 phr.

In one embodiment, in practice, sulfur vulcanized rubber productstypically are prepared by thermomechanically mixing rubber and variousingredients in a sequentially step-wise manner followed by shaping andcuring the compounded rubber to form a vulcanized product. In a morespecific embodiment, first, for the aforesaid mixing of the rubber andvarious ingredients, typically exclusive of sulfur and sulfurvulcanization accelerators (collectively “curing agents”), the rubber(s)and various rubber compounding ingredients are usually blended in atleast one, and optionally (in the case of silica filled low rollingresistance tires) two or more, preparatory thermomechanical mixingstage(s) in suitable mixers. In a further embodiment, such preparatorymixing is referred to as non-productive mixing or non-productive mixingsteps or stages. In a more specific embodiment, such preparatory mixingusually is conducted at temperatures in specifically in the range offrom about 140° C. to about 180° C., and more specifically in the rangeof from about 150° C. to about 160° C.

In one embodiment, subsequent to such preparatory mix stages, in a finalmixing stage, sometimes referred to as a productive mix stage, curingagents, and possibly one or more additional ingredients, are mixed withthe rubber compound or composition, typically at a temperature in arange of 50° C. to 130° C., which is a lower temperature than thoseutilized in the preparatory mix stages to prevent or retard prematurecuring of the sulfur curable rubber, which is sometimes referred to asscorching of the rubber composition.

In another embodiment, the rubber mixture, sometimes referred to as arubber compound or composition, typically is allowed to cool, sometimesafter or during a process of intermediate mill mixing, between theaforesaid various mixing steps, for example, to a temperature of about50° C. or lower.

In another embodiment herein, when it is desired to mold and to cure therubber, the rubber is placed into the appropriate mold and heated toabout at least 130° C. and up to about 200° C., which will cause thevulcanization of the rubber by the mercapto groups on the mercaptosilaneand any other free sulfur sources in the rubber mixture.

In one embodiment, by thermomechanical mixing, it is meant that therubber compound, or composition of rubber and rubber compoundingingredients, is mixed in a rubber mixture under high shear conditionswhere it autogenously heats up as a result of the mixing, primarily dueto shear and associated friction within the rubber mixture in the rubbermixer. In one embodiment, several chemical reactions can occur atvarious steps in the mixing and curing processes.

In one embodiment, the first reaction is a relatively fast reaction andis considered herein to take place between the filler and thealkoxysilyl group of the cyclic and/or bridging dialkoxymercaptofunctional silanes, —SiX where X is a hydrolysable group,—SiZ^(β) or SiZ^(θ), herein. In a further embodiment, such reaction canoccur at a relatively low temperature, such as, for example, about 120°C. In a further embodiment, the second reaction is considered herein tobe the reaction which takes place between the sulfur-containing portionof the silane, and the sulfur vulcanizable rubber at a highertemperature; for example, above about 140° C.

In one embodiment, another sulfur source can be used, for example, inthe form of elemental sulfur as S₈. In a more specific embodiment, asulfur donor is considered herein as a sulfur-containing compound thatliberates free, or elemental sulfur, at a temperature in a range ofabout 140° C. to about 190° C. In an even more specific embodiment, suchsulfur donors can be those such as the non-limiting examples ofpolysulfide vulcanization accelerators with at least two connectingsulfur atoms in their polysulfide bridge. In an even yet more specificembodiment, the amount of free sulfur source addition to the mixture canbe controlled or manipulated as a matter of choice relativelyindependently from the addition of the aforesaid cyclic and/or bridgingdialkoxy mercaptofunctional silane composition.

Thus, in one embodiment for example, the independent addition of asulfur source can be manipulated by the amount of addition thereof andby sequence of addition relative to addition of other ingredients to therubber mixture.

In another embodiment herein, a rubber composition is prepared by aprocess comprising the sequential steps of:

a) thermomechanically mixing, in at least one preparatory mixingoperation, in a first embodiment to a temperature of from about 140° C.to about 180° C. and in a second embodiment to a temperature of fromabout 150° to about 170° for a total mixing time in a first embodimentof from about 1 to about 20 minutes and in a second embodiment fromabout 4 to about 15 minutes, for such mixing operation(s):

-   -   i) about 100 parts by weight of at least one sulfur vulcanizable        rubber selected from the group consisting of conjugated diene        homopolymers and copolymers and copolymers of at least one        conjugated diene and aromatic vinyl compound,    -   ii) from about 5 to about 100 parts by weight of particulate        filler in a first embodiment and from about 25 to 80 parts by        weight of particulate filler in a second embodiment, wherein the        filler preferably contains from 0 to about 85 weight percent        carbon black, and,    -   iii) from about 0.05 to about 20 parts by weight filler of at        least one mercaptofunctional silane of Formula (1) of claim 1;

b) blending the mixture from step (a), in a final thermomechanicalmixing step, at a temperature of from about 50° C. to about 130° C. fora time sufficient to blend the rubber e.g., for from 1 to 30 minutes ina first embodiment and for 1 to 5 minutes in a second embodiment, and acuring agent at 0 to 5 parts by weight; and,

c) optionally curing said mixture at a temperature in the range of fromabout 130 to about 200° C. for a period of from about 5 to about 60minutes.

Suitable rubber component (a) (organic polymers) and fillers are wellknown in the art and are described in numerous texts, of which twoexamples include The Vanderbilt Rubber Handbook; R. F. Ohm, ed.; R. T.Vanderbilt Company, Inc., Norwalk, CT; 1990 and Manual For The RubberIndustry; T. Kempermann, S. Koch, J. Sumner, eds.; Bayer AG, Leverkusen,Germany; 1993. In yet an even further embodiment, some representativenon-limiting examples of suitable rubber component (a) (organicpolymers) include solution styrene-butadiene rubber (SSBR), emulsionstyrene-butadiene rubber (ESBR), natural rubber (NR), polybutadiene(BR), ethylene-propylene terpolymers (EPDM), and acrylonitrile-butadienerubber (NBR).

In one embodiment herein, the rubber composition component (a) iscomprised of at least one diene-based elastomer, or rubber. In an evenmore specific embodiment, suitable monomers for preparing the rubbersare conjugated dienes which are those such as the non-limiting examplesof isoprene and 1,3-butadiene; and suitable vinyl aromatic compoundswhich are those such as the non-limiting examples of styrene and alphamethyl styrene; and combinations thereof. Thus in a more specificembodiment, the rubber is a sulfur curable rubber. In a furtherembodiment, such diene based elastomer, or rubber, can be selected, fromthe non-limiting examples of at least one of cis-1,4-polyisoprene rubber(natural and/or synthetic), and preferably natural rubber), emulsionpolymerization prepared styrene/butadiene copolymer rubber, organicsolution polymerization prepared styrene/butadiene rubber,3,4-polyisoprene rubber, isoprene/butadiene rubber,styrene/isoprene/butadiene terpolymer rubber, cis-1,4-polybutadiene,medium vinyl polybutadiene rubber (35-50 percent vinyl), high vinylpolybutadiene rubber (50-75 percent vinyl), styrene/isoprene copolymers,emulsion polymerization prepared styrene/butadiene/acrylonitrileterpolymer rubber and butadiene/acrylonitrile copolymer rubber. Anemulsion polymerization derived styrene/butadiene (ESBR) is alsocontemplated as diene based rubbers for use herein such as those havinga relatively conventional styrene content of 20 to 28 percent boundstyrene or, for some applications, an ESBR having a medium to relativelyhigh bound styrene content, namely, a bound styrene content of 30 to 45percent. In an even further specific embodiment, emulsion polymerizationprepared styrene/butadiene/acrylonitrile terpolymer rubbers containing 2to 40 weight percent bound acrylonitrile in the terpolymer are alsocontemplated as diene based rubbers for use herein.

In another embodiment herein, the solution polymerization prepared SBR(SSBR) typically has a bound styrene content in a range of specificallyfrom about 5 to about 50, more specifically from about 9 to about 36,and most specifically of from about 20 to about 30 weight percent. In amore specific embodiment, polybutadiene elastomer can he convenientlycharacterized, for example, by having at least a 90 weight percentcis-1,4-content.

In one embodiment some representative non-limiting examples of suitablefiller materials include include metal oxides, such as silica (pyrogenicand precipitated), titanium dioxide, aluminosilicate, and alumina,siliceous materials, including clays and talc, and carbon black. In amore specific embodiment, particulate, precipitated silica is alsosometimes used for such purpose, particularly in connection with asilane. In one embodiment wherein the filler is a silica alone or incombination with one or more other fillers. In another specificembodiment in some cases, a combination of silica and carbon black isutilized for reinforcing fillers for various rubber products, includingtreads for tires. In one embodiment, alumina can be used either alone orin combination with silica. The term “alumina” can be described hereinas aluminum oxide, or Al₂O₃. In a further specific embodiment, thefillers can be hydrated or in anhydrous form. Use of alumina in rubbercompositions is known, see, for example, U.S. Pat. No. 5,116,886 and EP631 982, the contents of which are incorporated by reference herein.

In one embodiment there is provided herein a process for preparing arubber composition comprising adding to a rubber compositionreaction-forming mixture, such as a mixture of the herein describedrubber composition components (a), (b) and (c) in an effective amount ofat least one mercaptofunctional silane composition as described herein.In one embodiment an effective amount of mercaptofunctional silanecomposition, in a rubber composition reaction forming mixture, asdescribed herein, is specifically of from about 0.2 to about 20, morespecifically of from about 0.5 to about 15 and most specifically of fromabout 2 to about 10 weight percent of mercaptofunctional silane based onthe total weight of rubber composition reaction forming mixture. Inanother embodiment, reaction-forming mixture further comprises a filleras described herein and in an amount of specifically of from about 2 toabout 70, more specifically of from about 5 to about 50 and mostspecifically of from about 20 to about 40 weight percent of filler,based on the total weight of rubber composition reaction-formingmixture. In yet another embodiment reaction-forming mixture can evenfurther comprise a rubber component (a) described herein, and in anamount of specifically of from about 30 to about 98, more specificallyof from about 50 to about 95 and most specifically of from about 60 toabout 80 weight percent of rubber component based on the total weight ofrubber composition reaction forming mixture. In one embodiment herein,rubber composition as described herein can have amounts of components(a), (b) and (c) as described for rubber component reaction formingmixture.

In one embodiment, the mercaptofunctional silane compositions thatcontain cyclic and/or bridging dialkoxysilyl groups can be premixed, orpre-reacted, with the filler particles or added to the rubber mix duringthe rubber and filler processing, or mixing stage. In anotherembodiment, if the silane and filler are added separately to the rubbermix during the rubber and filler mixing, or processing stage, it isconsidered that the organofunctional silane compositions that containcyclic and/or bridging dialkoxysilyl groups then couple in situ to thefiller.

In one embodiment herein, vulcanized rubber composition should contain asufficient amount of filler to contribute a reasonably high modulus andhigh resistance to tear. In a specific embodiment, the combined weightof the filler can be as low as about 5 to about 100 phr, but is morespecifically of from about 25 to about 85 phr, and most specifically offrom about 50 to about 70 phr.

In one embodiment the term “filler” as used herein means a substancethat is added to the elastomer to either extend the elastomer or toreinforce the elastomeric network. Reinforcing fillers are materialswhose moduli are higher than the organic polymer of the elastomericcomposition and are capable of absorbing stress from the organic polymerwhen the elastomer is strained. In one embodiment fillers includedfibers, particulates, and sheet-like structures and can be composed ofinorganic minerals, silicates, silica, clays, ceramics, carbon, organicpolymers, diatomaceous earth. In one embodiment the filler herein can beessentially inert to the silane with which it is admixed, or it can bereactive therewith.

In one embodiment the term “particulate filler” as used herein means aparticle or grouping of particles to form aggregates or agglomerates. Inone embodiment the particulate filler herein can be essentially inert tothe silane with which it is admixed, or it can be reactive therewith.

In one embodiment the term “carrier” as used herein means a porous orhigh surface area filler or organic polymer that has a high adsorptionor absorption capability and is capable of carrying up to 75 percentliquid silane while maintaining its free-flowing and dry properties. Inone embodiment the carrier filler or carrier polymer herein isessentially inert to the silane and is capable of releasing ordeabsorbing the liquid silane when added to the elastomeric composition.

In an embodiment, fillers of the present invention can be used ascarriers for liquid silanes and reinforcing fillers for elastomers inwhich the mercapto functional silane, and more specifically, themercaptofunctional silane (1) is capable of reacting or bonding with thesurface. In one embodiment, the fillers that are used as carrier shouldbe non-reactive with the mercaptosilane of this invention. In oneembodiment the non-reactive nature of the fillers is demonstrated byability of the merpcaptosilane to be extracted at greater than 50percent of the loaded silane using an organic solvent. In one embodimentthe extraction procedure is given in U.S. Pat. No. 6,005,027, which isincorporated herein by reference. In one embodiment, carriers include,but are not limited to, porous organic polymers, carbon black,diatomaceous earth, and silicas that characterized by relatively lowdifferential of less than 1.3 between the infrared absorbance at 3502cm⁻² of the silica when taken at 105° C. and when taken at 500° C., asdescribed in U.S. Pat. No. 6,005,027. In one embodiment, the amount ofmercapto functional silane that can be loaded on the carrier is between0.1 and 70 percent. In another embodiment, the mercpato functionalsilane is load on the carrier at concentrations between 10 and 50percent. In yet another embodiment, the filler is a particulate filler.

In one embodiment herein reinforcing fillers useful herein includefillers in which the silanes are reactive with the surface of thefiller. In one embodiment some representative examples of the fillersinclude, but are not limited to, inorganic fillers, siliceous fillers,metal oxides such as silica (pyrogenic and/or precipitated), titanium,aluminosilicate and alumina, clays and talc, and the like. In oneembodiment herein, particulate, precipitated silica is useful for suchpurpose, particularly when the silica has reactive surface silanols. Inone embodiment of the present invention, a combination of 0.1 to 20percent of mercapto functional silane, and more specifically, themercapto functional silanes (1) and 80 to 99.9 percent silica or otherreinforcing fillers is utilized to reinforce various rubber products,including treads for tires. In another embodiment, a filler iscomprising from about 0.5 to about 10 percent mercaptofunctional silane,and more specifically, mercapto functional silane (1) and about 90 toabout 99.5 weight percent particulate filler. In another embodimentherein, alumina can be used alone with the mercapto functional silane,and more specifically, mercaptofunctional silane (1) or in combinationwith silica and the mercaptofunctional silane. In one embodiment hereinthe term, alumina, can be described herein as aluminum oxide, or Al₂O₃.In a further embodiment herein, the fillers may be in the hydrated form.

In one embodiment the filler can be essentially inert to the silane withwhich it is admixed as is the case with carbon black or organicpolymers, or it can be reactive therewith, e.g., the case with carrierspossessing metal hydroxyl surface functionality, e.g., silicas and othersiliceous particulates which possess surface silanol functionality.

In one embodiment herein, precipitated silica is utilized as filler. Ina more specific embodiment, the silica filler herein can ascharacterized by having a BET surface area, as measured using nitrogengas, specifically in the range of from about 40 to about 600 m²/g, andmore specifically in a range of from about 50 to about 300 m²/g and mostspecifically in a range of from about 100 to about 150 m²/g. In anotherspecific embodiment, the BET method of measuring surface area isdescribed in the Journal of the American Chemical Society, Volume 60,page 304 (1930), which is the method used herein. In yet anotherspecific embodiment, the silica typically can also be characterized byhaving a dibutylphthalate (DBP) absorption value in a range ofspecifically from about 100 to about 350, more specifically from about150 to about 300 and most specifically from about 200 to about 250. Inan even further specific embodiment, further, useful silica fillers, aswell as the aforesaid alumina and aluminosilicate fillers, can beexpected to have a CTAB surface area in a range of from about 100 toabout 220 m²/g. In an even further specific embodiment, the CTAB surfacearea is the external surface area as evaluated by cetyltrimethylammonium bromide with a pH of 9; the method is described inASTM D 3849.

Mercury porosity surface area is the specific surface area determined bymercury porosimetry. In this technique, mercury is penetrated into thepores of the sample after a thermal treatment to remove volatiles. In amore specific embodiment, set-up conditions can be suitably described asusing a 100 mg sample; removing volatiles during 2 hours at 105° C. andambient atmospheric pressure; and ambient to 2000 bars pressuremeasuring range. In another more specific embodiment, such evaluationcan be performed according to the method described in Winslow, et al. inASTM bulletin, p.39 (1959) or according to DIN 66133; for such anevaluation, a CARLO-ERBA Porosimeter 2000 can be used. In oneembodiment, the average mercury porosity specific surface area for theselected silica filler should be in a range of specifically from about100 to about 300 m²/g, more specifically from about 150 to about 275m²/g, and most specifically from about 200 to about 250 m²/g.

In one embodiment, a suitable pore size distribution for the silica,alumina and aluminosilicate according to such mercury porosityevaluation is considered herein to be: five percent or less of its poreshaving a diameter of less than about 10 nm; from about 60 to about 90percent of its pores have a diameter of from about 10 to about 100 nm;from 10 to about 30 percent of its pores having a diameter of from about100 to about 1,000 nm; and from about 5 to about 20 percent of its poreshave a diameter of greater than about 1,000 nm. In a second embodiment,the silica can be expected to have an average ultimate particle size,for example, in the range of from about 0.01 to about 0.05 μm asdetermined by electron microscopy, although the silica particles can beeven smaller, or possibly larger, in size. In one embodiment, variouscommercially available silicas can be considered for use herein such as,those available from PPG Industries under the HI-SIL trademark, inparticular, HI-SIL 210, and 243; silicas available from Rhone-Poulenc,e.g., ZEOSIL 1165MP; silicas available from Degussa, e.g., VN2 and VN3,etc. and silicas available from Huber, e.g., HUBERSIL 8745.

In one embodiment, where it is desired for rubber composition, whichcontains both a siliceous filler such as silica, alumina and/oraluminosilicates and also carbon black reinforcing pigments, to beprimarily reinforced with silica as the reinforcing pigment, it is oftenmore specific that the weight ratio of such siliceous fillers to carbonblack is at least 3/1 and preferably at least 10/1 and, thus, in a rangeof 3/1 to 30/1. In a more specific embodiment, the filler can comprisefrom about 15 to about 95 weight percent precipitated silica, aluminaand/or aluminosilicate and, correspondingly from about 5 to about 85weight percent carbon black, wherein the said carbon black has a CTABvalue in a range of from about 80 to about 150. In one specificembodiment, alternatively, the filler can comprise from about 60 toabout 95 weight percent of said silica, alumina and/or aluminosilicateand, correspondingly, from about 40 to about 5 weight percent of carbonblack. In another specific embodiment, the siliceous filler and carbonblack can be pre-blended or blended together in the manufacture of thevulcanized rubber.

In one embodiment, the rubber composition herein can be compounded bymethods known in the rubber compounding art, such as mixing the varioussulfur-vulcanizable constituent rubbers with various commonly usedadditive materials as, for example, curing aids such as sulfur,activators, retarders and accelerators, processing additives such asoils, resins e.g., tackifying resins, silicas, plasticizers, fillers,pigments, fatty acid, zinc oxide, waxes, antioxidants and antiozonants,peptizing agents, and reinforcing materials such as, for example, carbonblack, and the like. In another specific embodiment, depending on theintended use of the sulfur vulcanizable and sulfur vulcanized material(rubbers), the additives mentioned herein are selected and commonly usedin conventional amounts.

In one embodiment, the vulcanization can be conducted in the presence ofan additional sulfur vulcanizing agent. In one specific embodiment, somenon-limiting examples of suitable sulfur vulcanizing agents include,e.g., elemental sulfur (free sulfur) or sulfur donating vulcanizingagents, such as the non-limiting examples of, an amino disulfide,polymeric polysulfide or sulfur olefin adducts, which are conventionallyadded in the final, productive, rubber composition mixing step. Inanother specific embodiment, the sulfur vulcanizing agents (which arecommon in the art) are used, or added in the productive mixing stage, inan amount ranging from about 0.4 to about 3 phr, or even, in somecircumstances, up to about 8 phr, with a range of from about 1.5 toabout 2.5 phr, and in some cases from about 2 to about 2.5 phr, beingmost specific.

In one embodiment, vulcanization accelerators, i.e., additional sulfurdonors, can also be used. In one embodiment, it will be appreciated thatthey can be those such as the non-limiting examples of benzothiazole,alkyl thiuram disulfide, guanidine derivatives, and thiocarbamates. Inanother specific example, representative of such accelerators are, e.g.,but not limited to, mercapto benzothiazole, tetramethyl thiuramdisulfide, benzothiazole disulfide, diphenylguanidine, zincdithiocarbamate, alkylphenoldisulfide, zinc butyl xanthate,N-dicyclohexyl-2-benzothiazolesulfenamide,N-cyclohexyl-2-benzothiazolesulfenamide,N-oxydiethylenebenzothiazole-2-sulfenamide, N,N-diphenylthiourea,dithiocarbamylsulfenamide, N,N-diisopropylbenzothiozole-2-sulfenamide,zinc-2-mercaptotoluimidazole, dithiobis(N-methyl piperazine),dithiobis(N-beta-hydroxy ethyl piperazine), dithiobis(dibenzyl amine)and combinations thereof. In another specific embodiment, otheradditional sulfur donors, include, e.g., thiuram and morpholinederivatives. In a more specific embodiment, representative of suchdonors include, e.g., but are not limited to, dimorpholine disulfide,dimorpholine tetrasulfide, tetramethyl thiuram tetrasulfide,benzothiazyl-2,N-dithiomorpholide, thioplasts, dipentamethylenethiuramhexasulfide, disulfidecaprolactam and combinations thereof.

In one embodiment, accelerators are used to control the time and/ortemperature required for vulcanization and to improve the properties ofthe vulcanizate. In one embodiment, a single accelerator system can beused, i.e., a primary accelerator. In another embodiment, conventionallyand more specifically, a primary accelerator(s) is used in total amountsranging from about 0.5 to about 4, preferably from about 0.8 to about1.5 phr. In a more specific embodiment, combinations of a primary and asecondary accelerator can be used with the secondary accelerator beingused in smaller amounts (e.g., from about 0.05 to about 3 phr) in orderto activate and to improve the properties of the vulcanizate. In yet afurther embodiment, delayed action accelerators can also be used. In yetan even further embodiment, vulcanization retarders can also be used. Inone embodiment, suitable types of accelerators are those such as thenon-limiting examples of amines, disulfides, guanidines, thioureas,thiazoles, thiurams, sulfenamides, dithiocarbamates, xanthates andcombinations thereof. In a more specific embodiment, the primaryaccelerator is a sulfenamide. In another specific embodiment, if asecond accelerator is used, the secondary accelerator is morespecifically a guanidine, dithiocarbamate or thiuram compound.

In one embodiment some non-limiting amounts of tackifier resins, ifused, can be from about 0.5 to about 10 phr, usually from about 1 toabout 5 phr. In one specific embodiment, typical amounts of processingaids comprise from about 1 to about 50 phr. In another specificembodiment, such processing aids can include, the non-limiting examplesof aromatic, naphthenic and/or paraffinic processing oils, andcombinations thereof. In one more specific embodiment, typical amountsof antioxidants are from about 1 to about 5 phr. In one other specificembodiment, representative antioxidants include, the non-limitingexamples of diphenyl-p-phenylenediamine and others, e.g., thosedisclosed in the Vanderbilt Rubber Handbook (1978), pages 344-346. Inyet another embodiment, typical amounts of antiozonants, are from about1 to about 5 phr. In one more embodiment, typical amounts of fattyacids, if used, which can include the non-limiting example of stearicacid, are from about 0.5 to about 3 phr. In one more embodiment, typicalamounts of zinc oxide are from about 2 to about 5 phr. In yet anotherspecifice embodiment, typical amounts of waxes are from about 1 to about5 phr. In one embodiment, often microcrystalline waxes are used. Inanother embodiment, typical amounts of peptizers are from about 0.1 toabout 1 phr. In yet a further embodiment, typical peptizers include, thenon-limiting examples of pentachlorothiophenol, dibenzamidodiphenyldisulfide and combinations thereof.

In one embodiment herein, rubber compositions herein can be used forvarious purposes. In one specific embodiment, for example, they can beused for the non-limiting examples of various tire compounds, shoesoles, hoses, cable jackets, gaskets, and other industrial goods. In amore specific embodiment, such articles can be built, shaped, molded andcured by various known and conventional methods as is readily apparentto those skilled in the art. In one even more specific embodiment, oneparticularly useful application of the rubber compositions herein is forthe manufacture of tire treads. In one embodiment, an advantage oftires, tire treads, or other articles of manufacture derived from therubber compositions herein is that they suffer from less VOC emissionsduring their lifetime and use as a result of having been manufacturedfrom a rubber compound that contains less residual silane ethoxy groupsthan do rubber compounds of the known and currently practiced art. In amore specific embodiment, this is a direct result of having useddialkoxy-functional silane coupling agents in their manufacture, whichcontain fewer or essentially no ethoxy groups on silicon, relative tothe blends of mercaptosilane coupling agents of the currently known andpracticed art. In one embodiment, the lack or reduction of ethoxysilanegroups in the coupling agents used results in fewer residual ethoxygroups on silicon after the article of manufacture is produced, fromwhich less or no ethanol can be released by hydrolysis of the residualethoxysilane groups by exposure of the article of manufacture to waterduring use.

All references cited herein are incorporated by reference herein intheir entirety.

The invention can be better understood by reference to the followingexamples in which the parts and percentages are by weight unlessotherwise indicated.

EXAMPLE 1

3-Mercaptopropyltriethoxysilane (obtained from General Electric underthe trade name Silquest A-1891, 514.3 grams, 2.16 mole), and2-methyl-1,3-propanediol (purchased from Aldrich, 194.4 grams, 2.16moles) were charged into a 1-liter round-bottomed flask equipped with amagnetic stirrer, short path condenser and receiver flask. Purolite(purchased from Rohm & Haas, 3.5 grams) was added to the reaction flaskand the mixture was heated to 50° C. under a vacuum of initially 60 torrto about 1 torr for about 3 hours. Ethanol (185 grams, 4.02 moles) wascollected. The reaction product was pressured filtered through a3.5-micron pad. The weight of the product collected was 501.7 grams.GC/MS found a complex mixture that contained3-({3-[2-mercapto-propyl)-5-methyl-[1,3,2]doxasilinan-2-yloxy]-2-methyl-propyl}-diethoxy-silyanyl)-propane-1-thioland3-2-{3-[2-(3-mercapto-propyl)-5-methyl-[1,3,2]dioxasilinan-2-yloxy]-2-methyl-propoxy}-5-methyl-[1,3,2]dioxasilinan-2-yl)-propane-1-thiol.

EXAMPLE 2

3-Mercaptopropyltriethoxysilane (obtained from General Electric underthe trade name Silquest A-1891, 438.8 grams, 1.84 mole), and2-methyl-1,3-propanediol (purchased from Aldrich, 331.7 grams, 3.68moles) were charged into a 1-liter round-bottomed flask equipped with amagnetic stirrer, short path condenser and receiver flask. Sulfuric acid(0.39 gram) was added to the reaction flask and the mixture was heatedto 50° C. under a vacuum of initially 40 torr to about 1 torr (fullvaccum) 3.5 hours. Ethanol (263 grams, 5.71 moles) was collected. Thereaction product was then neutralized with 1.44 grams of 21% sodiumethoxy in ethanol and then stripped 1.5 hours. The weight of the productcollected was 485.6 grams. GC analysis found a complex mixture thatcontained3-({3-[2-mercapto-propyl)-5-methyl-[1,3,2]dioxasilinan-2-yloxy]-2-methyl-propyl}-diethoxy-silyanyl)-propane-1-thioland higher molecular weight components.

EXAMPLE 3

3-Mercaptopropyltriethoxysilane (obtained from General Electric underthe trade name Silquest A-1891, 720.5 grams, 3.02 mole), and2-methyl-1,3-propanediol (purchased from Aldrich, 817.0 grams, 9.07moles) were charged into a 3-liter round-bottomed flask equipped with amagnetic stirrer, short path condenser and receiver flask. Sulfuric acid(0.78 gram) was added to the reaction flask and the mixture was heatedto about 50° C. under a vacuum of initially 30 torr to about 10 torr for3.5 hours. Ethanol (389.4 grams, 8.5 moles) was collected. The reactionproduct was then neutralized with 2.5 grams of 21% sodium ethoxy inethanol and then stripped 1 hour. The weight of the product collectedwas 1108.9 grams.

EXAMPLE 4

3-Mercaptopropyltriethoxysilane (100 grams, 0.42 mole), and2-methyl-2,4-pentanediol (50 grams, 0.42 mole) are charged into a1-liter round-bottomed flask equipped with a magnetic stirrer, shortpath condenser and receiver flask. Titanium isopropoxide (0.85 gram) isadded to the reaction flask and the mixture is heated to 70° C. under avacuum of initially about 370 torr for 1 hour. 2-Methyl-1,3-propanediol(18.9 grams, 0.21 mole) is added and heated.

COMPARATIVE EXAMPLES 5 and 6 and EXAMPLES 7, 8, 9 and 10

Cured rubber compositions in the form of plaques were prepared and theirphysical and dynamic properties measured to determine effect of loading.

A typical silica-rubber SBR formulation was used as described below inTable 1. Mixing was carried out in a 1.7-liter Banbury tangential mixer.

TABLE 1 Silica-Silane/Rubber Formulation PHR Components 103.2 sSBR (BunaVSL 5025-1 from Bayer AG) 25 BR (Budene 1207 from Goodyear) 80 silica(Zeosil 1165MP from Rhodia) 3.0 carbon black (N-330) Variable silane 4.5oil (Sundex 8125 from Sun Oil) 2.5 zinc oxide (Kadox 720C fromZincCorp.) 1.0 stearic acid (Industrene R from Witco, Crompton) 2.0 6PPD (Flexzone 7P from Uniroyal, Crompton) 1.5 Wax (Sunproof Improvedfrom Uniroyal, Crompton) Final Mix Ingredients 1.4 sulfur (RubbermakersSulfur 104 from Harwick) 1.7 CBS (Delac S from Uniroyal, Crompton) 2.0DPG (from Uniroyal, Crompton)

The procedure which was used for preparing a single non-productive mixis presented in Table 2 below.

TABLE 2 One Pass Procedure; Cooling with water @ 25° C., 68% fillfactor: Step Procedure 1 Add polymers, RDM (ram down mix) 30 seconds 2Add 50% silica, all silane, RDM 30 seconds 3 Add remaining 50% silica,oil, RDM 30 seconds 4 Dust down, RDM 20 seconds 5 Add ZnO, steric acid,Flexzone 7P, wax and carbon black, RDM 60 seconds 6 Dust down, RDM to170° C. (in approx. 2 minutes) by increasing rotor speed 7 Hold at 170°C. for 8 minutes by changing speeds on the mixer. 8 Dump, sheet off rollmill @ 65–70° C. to cool

The procedure for preparing a single productive mix involved addingsulfur and accelerators (primary and secondary) into a masterbatchprepared as described in Table 2 on a two-roll mill at 65 to 70° C.After all the silica filler, silane and oil were incorporated into agiven mix, the rpm of the rotors was raised so as to achieve the desiredsilanization temperature. The mix was then held at that temperature for8 minutes. The mix procedures are shown in Table 2, above.

Curing and testing of the cured rubber compositions in the form ofplaques were carried out according to ASTM standards. In addition, smallstrain dynamic tests were carried out on a Rheometrics Dynamic Analyzer(ARES—Rheometrics Inc.). The specific curing procedure, measurements andmeasuring procedures were as follows:

Curing Procedure/Measurement Testing Standard Mooney viscosity andscorch ASTM D1646 Oscillating disc rheometry ASTM D2084 Curing of testplaques ASTM D3182 Stress-strain properties ASTM D412 Heat build-up ASTMD623

Dynamic Mechanical Properties:

Payne effect strain sweeps were carried out from dynamic strainamplitudes of 0.01% to about 25% shear strain amplitude at 10 Hz and 60°C. The dynamic parameters, G′_(initial), ΔG′, G″_(max), tan δ_(max) wereextracted from the non-linear responses of the rubber compounds at smallstrains. In some cases, steady state values of tan δ were measured after15 minutes of dynamic oscillations at strain amplitudes of 35% (at 60°C.). Temperature dependence of dynamic properties were also measuredfrom about −80° C. to +80° C. at small strain amplitudes (1 or 2%) at afrequency of 10 Hz. The rheological, physical and dynamic properties ofthe rubber compounds, Comparative Examples 5 and 6 (silane is SilquestA-1891 silane) and Example 7, 8, 9 and 10 (silane from Example 3) inTable 3.

TABLE 3 The rheological, physical and dynamic properties of rubberExample No. Comp. 5 Comp. 6 7 8 9 10 Silane loading phr 4 6.5 2 3 4 6.5Mooney Properties Viscosity at 100° C. (ML1 + 4) 89.52 78.77 73.6 70.9480.58 74.3 MV at 135° C. (MS1+) 41.62 53.77 31.56 29.46 35.61 41.48Scorch at 135° C. (MS1 + t₃) (min) 6.2 3.18 10.26 8.22 7.21 4.11 Cure at135° C. (MS1 + t₁₈) (min) 9.28 4 14.1 12.17 10.34 5.1 Rheometer (ODR)Properties, (1° arc at 149° C.) M_(L) (dN-m) 15.79 13.93 12.14 10.6712.81 12.71 M_(H) (dN-m) (30 min. timer) 33.63 35.09 32.51 31.31 34.8633.69 t90 (min) (30 min. timer) 18.52 19.35 17.79 15.42 13.13 5.97t_(s1) (min) 3.67 1.83 4.38 4.71 4.25 2.92 M_(H) − M_(L) 17.84 21.1620.38 20.64 22.05 20.98 Physical Properties, (cured t90 at 149° C.)Hardness (Shore A) 56.3 58.3 59 56.3 57.7 57.7 Tensile (MPa) 15.10 12.2619.76 19.44 18.56 15.54 Elongation (%) 312 250 492 414 354 306  25%Modulus (MPa) 0.73 0.84 0.83 0.76 0.76 0.90 100% Modulus (MPa) 2.05 2.501.63 1.73 2.01 2.35 300% Modulus (MPa) 14.14 “_” 8.71 11.36 14.21 13.97Reinforcement Index, (300%/25%) 19.37 “—” 10.46 14.94 18.70 15.51Reinforcement Index, (300%/100%) 6.91 “—” 5.34 6.55 7.07 5.95 AbrasionLoss (DIN) (mm³) 107 118 133 115 108 114 Dynamic Properties, (cured t90at 149° C.) Non-linearity (0–10%) 60° C. G′_(initial) (MPa) 2.39 2.473.89 2.27 2.98 2.16 □G′ (MPa) 0.88 1.01 2.13 0.91 1.41 0.78 G″_(max)(MPa) 0.30 0.30 0.55 0.28 0.34 0.23 tan

_(max) 0.16 0.15 0.19 0.15 0.15 0.13 Temperature Dependence tan

0° C. 0.54 0.54 0.51 0.57 0.48 0.58 tan

60° C. 0.14 0.14 0.17 0.14 0.14 0.12 G′ 0° C. (MPa) 6.10 5.62 9.68 6.566.12 6.42 G′ 60° C. (MPa) 1.86 1.91 2.59 1.71 2.02 1.74

EXAMPLES 11, 12, 13 and 14

The rubber compounds were prepared according to the procedure describedin Comparative Example 5. The fill factor was 72 percent, and two passeswere used Example 11. The data shows the effect of non-productive mixingtemperature on performance of the rubber. The data are presented inTable 4.

TABLE 4 The rheological, physical and dynamic properties of rubberExample No 11 12 13 14 Silane loading phr 3.7 4 4 4 Temperature 140 160170 180 Mooney Properties Viscosity at 100° C. (ML1 + 4) 101 75.13 80.5878.35 MV at 135° C. (MS1+) 59 32.4 35.61 34.49 Scorch at 135° C. (MS1 +t₃) 3.4 7.31 7.21 7.53 (min) Cure at 135° C. (MS1 + t₁₈) (min) 4.1 10.4210.34 11.12 Rheometer (ODR) Properties, (1° arc at 149° C.) M_(L) (dN-m)16.0 12.49 12.81 12.95 M_(H) (dN-m) (30 min. timer) 31.0 34.34 34.8634.7 t90 (min) (30 min. timer) 5.1 10.87 13.13 11.64 t_(s1) (min) 2.14.49 4.25 4.82 M_(H) − M_(L) 15.0 21.85 22.05 21.76 Physical Properties,(cured t90 at 149° C.) Hardness (Shore A) 60 57.7 57.7 58.3 Tensile(MPa) 15.5 19.64 18.56 17.18 Elongation (%) 300 381 354 343  25% Modulus(MPa) 0.87 0.72 0.76 0.76 100% Modulus (MPa) 2.36 1.89 2.01 2.01 300%Modulus (MPa) 15.1 13.39 14.21 13.83 Reinforcement Index, (300%/25%)17.4 18.55 18.70 18.15 Reinforcement Index, 6.40 7.08 7.07 6.87(300%/100%) Abrasion Loss (DIN) (mm³) 93 108 104 Dynamic Properties,(cured t90 at 149° C.) Non-linearity (0–10%) 60° C. G′_(initial) (MPa)1.78 2.73 2.98 2.43 □G′ (MPa) 0.45 1.21 1.41 1.10 G″_(max) (MPa) 1.750.35 0.34 0.28 tan

_(max) 0.11 0.15 0.15 0.16 Temperature Dependence tan

0° C. 0.63 0.57 0.48 0.44 tan

60° C. 0.10 0.14 0.14 0.15 G′ 0° C. (MPa) 6.27 7.22 6.12 5.38 G′ 60° C.(MPa) 1.60 2.00 2.02 1.81

While the invention has been described with reference to a number ofexemplary embodiments, it will be understood by those skilled in the artthat various changes can be made and equivalents can be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications can be made to adapt a particular situationor material to the teachings of the invention without departing fromessential scope thereof. Therefore, it is intended that the inventionnot be limited to any particular exemplary embodiment disclosed herein.

1. A filled elastomer composition comprising: a) at least one rubbercomponent; b) at least one particulate filler; and, c) at least onemercaptofunctional silane general Formula (1):[HSG¹SiZ^(θ)Z^(β)]_(m)[HSG²SiZ^(β) ₃]_(n)[HSG³SiZ^(β)₂X]_(o)[[HSG⁴SiZ^(β)X₂]_(p)   (1) wherein: each occurrence of G¹, G²,G³, and G⁴ is independently a hydrocarbylene group containing from 1 to30 carbon atoms selected from the group consisting of divalent groupsderived by substitution of a hydrogen on alkyl, alkenyl, aryl, oraralkyl or a substituted divalent heterocarbon containing 2 to 30 carbonatoms and one or more etheric oxygen (—O—) and/or sulfur (—S—) atoms;each occurrence of X is independently selected from the group consistingof —Cl, —Br, RO—, RC(═O)O—, R₂C═NO—, R₂NO—, —R, (HO)_(d-1)G⁵O—, whereineach R is independently selected from the group consisting of hydrogen,straight, cyclic or branched alkyl that can or can not containunsaturation, alkenyl groups, aryl groups, and aralkyl groups, whereineach R, other than hydrogen, contains from 1 to 18 carbon atoms, G⁵ isindependently a hydrocarbylene group of from 2 to 15 carbon atoms or adivalent heterocarbon group of from about 4 to about 15 carbon atomscontaining one or more etheric oxygen atoms; each occurrence of Z^(β),which forms a bridging structure between two silicon atoms, is[—OG⁵(OH)_(d-2)O—]_(0.5), wherein each occurrence of G⁵ is independentlyselected form the group consisting of a hydrocarbylene group from 2 to15 carbon atoms or a divalent heterocarbon group of from 4 to 15 carbonatoms containing one or more etheric oxygen atoms; each occurrence ofZ^(θ), which forms a cyclic structure with a silicon atom, isindependently given by —OG⁵(OH)_(d-2)O—, wherein G⁵ is independentlyselected form the group consisting of a hydrocarbylene group of from 2to 15 carbon atoms or a divalent heterocarbon group of from 4 to 15carbon atoms containing one or more etheric oxygen atoms; eachoccurrence of subscripts d, m, n, o and p independently is an integerwherein d is from 2 to 6 in a first embodiment, 2 or 3 in a secondembodiment and 2 in a third embodiment; m is 0 to 20; n is 0 to 18; o is0 to 20; and, p is 0 to 20, with the proviso that m+n+o+p is equal to orgreater than
 2. 2. The filled elastomer composition of claim 1 whereinrubber component (a) is at least one member selected from the groupconsisting of styrene-butadiene rubber, emulsion styrene-butadienerubber, natural rubber, polybutadiene rubber, ethylene-propylene-dienemonomer terpolymer and acrylonitrile-butadiene rubber.
 3. The filledelastomer composition of claim 1 wherein rubber component (a) is atleast one member selected from the group consisting of naturalcis-1,4-polyisoprene rubber, synthetic cis-1,4-polyisoprene rubber,emulsion polymerization-prepared styrene/butadiene copolymer rubber,organic solution polymerization-prepared styrene/butadiene rubber,3,4-polyisoprene rubber, isoprene/butadiene rubber,styrene/isoprenelbutadiene terpolymer rubber, cis-1,4-polybutadiene,medium vinyl polybutadiene rubber of about 35 to about 50 percent vinylcontent, high vinyl polybutadiene rubber of about 50 to about 75 percentvinyl content, styrene/isoprene copolymer, emulsionpolymerization-prepared styrene/butadiene/acrylonitrile terpolymerrubber and butadiene/acrylonitrile copolymer rubber.
 4. The filledelastomer composition of claim 1 wherein rubber component (a) is atleast one member selected from the group consisting of emulsionpolymerization-derived styreneibutadiene having a bound styrene contentof from about 20 to about 28 weight percent styrene or, an emulsionpolymerization-derived styrene/butadiene having a bound styrene contentof from about 30 to about 45 weight percent and an emulsionpolymerization-prepared styrene/butadiene/acrylonitrile terpolymerrubber containing from about 2 to about 40 weight percent boundacrylonitrile.
 5. The filled elastomer composition of claim 1 whereinrubber component (a) is a solution styrene-butadiene rubber having abound styrene content of from about 5 to about 50 weight percent.
 6. Thefilled elastomer composition of claim 1 wherein rubber component (a) isa solution styrene-butadiene rubber having a bound styrene content offrom about 9 to about 36 weight percent.
 7. The filled elastomercomposition of claim 6 wherein rubber component (a) is a solutionstyrene-butadiene rubber having a bound styrene content of from about 20to about 30 weight percent.
 8. The filled elastomer composition of claim1 wherein rubber component(a) is a polybutadiene rubber having a cis-1,4content of at least about 90 weight percent.
 9. The filled elastomercomposition of claim 1 wherein particulate filler (b) is at least onemember selected from the group consisting of metal oxide, siliceousmaterial and carbon black.
 10. The filled elastomer composition of claim9 wherein the metal oxide is at least one member selected from the groupconsisting of silica, titanium and alumina; and, the siliceous materialis at least one member of the group consisting of aluminosilicate, clayand talc.
 11. The filled elastomer composition of claim 10 whereinparticulate filler (b) is at least one member selected from the groupconsisting of mixtures of silica and carbon black and mixtures of silicaand alumina.
 12. The filled elastomer composition of claim 1 wherein inmercaptofunctional silane (c): each occurrence of G¹, G², G³ and G⁴ isindependently a hydrocarbylene group containing from 1 to 30 carbonatoms derived by substitution of a hydrogen on alkyl, alkenyl, aryl, oraralkyl; each occurrence of Z^(β), which forms a bridging structurebetween two silicon atoms, is independently [—O(R⁰CR⁰)_(f)O—]_(0.5),wherein each occurrence of R⁰ is independently given by one of themembers for R, and f is from 2 to 15; each occurrence of Z^(θ), whichforms a cyclic structure with a silicon atom, is independently[—O(R⁰CR⁰)_(f)O—]_(0.5), wherein each occurrence of R⁰ is independentlygiven by one of the members for R, and f is 2 to 15; each occurrence ofX is independently —OR, wherein each occurrence of R is independentlyselected from the group consisting of straight, cyclic and branchedalkyl, alkenyl, aryl and aralkyl containing up to 18 carbon atoms; and,each occurrence of m, n, o, and p independently is an integer wherein mis from 0 to 20, n is specifically from 0 to 18, o is from 0 to 20, andp is from 0 to 20, with the proviso that m+n+o+p is equal to or greaterthan
 2. 13. The filled elastomer composition of claim 2 wherein inmercaptofunctional silane (c) each occurrence of G¹, G², G³ and G⁴ isindependently a straight or branched chain alkylene group of up to 6carbon atoms; each occurrence of R⁰ is independently hydrogen or astraight or branched chain alkyl group of up to 6 carbon atoms and f is2 to 4; and, m is 0 to 5, n is 0 to 4, o is 0 to 5 and p is 0 to
 5. 14.The filled elastomer composition of claim 3 wherein inmercaptofunctional silane (c) each occurrence of G¹, G², G³ and G⁴ isindependently 3 carbon atoms, each occurrence of R⁰ is independentlyhydrogen or straight or branched chain alkyl group of 1 to 3 carbonatoms and f is 2 or 3; and, m is 0 or 1, n is 1 or 2, o is 1 or 2 and pis 0 or
 1. 15. The filled elastomer composition of claim 1 wherein inmercaptofunctional silane (c): each occurrence of G¹, G², G³ and G⁴ isindependently a group derived by substitution of hydrogen on alkyl,alkenyl, aryl, or aralkyl having up to 30 carbon atoms; each occurrenceof X is independently selected from the group consisting of —Cl, —Br,RO—, RC(═O)O—, R₂C═NO—, R₂NO—, R₂N—, —R, (HO)_(d-1)G⁵O—, HO(CR⁰₂)_(f)O—, and HO(CR⁰ ₂CR⁰ ₂O)_(e)—, wherein each R is independentlyselected from the group consisting of hydrogen or straight, cyclic orbranched alkyl, alkenyl, aryl, and aralkyl groups of up to 18 carbonatoms; G⁵ is independently a hydrocarbylene group of from 2 to 15 carbonatoms or a heterocarbylene group of from 4 to 15 carbon atoms containingone or more etheric oxygen atoms; R⁰ is independently given by one ofthe members for R; each occurrence of Z^(β), which forms a bridgingstructure between two silicon atoms, is independently selected from thegroup consisting of, [—OG⁵(OH)_(d-2)O—]_(0.5), [—O(CR⁰ ₂CR⁰₂O)_(e)—]_(0.5) and [—O(R⁰CR⁰)_(f)O—]_(0.5), wherein each occurrence ofR⁰ is independently given by one of the members listed for R; eachoccurrence of Z^(θ), which forms a cyclic structure with a silicon atom,is independently given by —OG⁴(OH)_(d-2)O—, —O(CR⁰ ₂CR⁰ ₂O)_(e)— and—O(R⁰CR⁰)_(f)O— wherein each occurrence of R⁰ is independently given byone of the members for R; and, each occurrence of the subscripts d, e,f, m, n, o and p is independently an integer wherein d is from 2 to 6, eis from 2 to 7, f is from 2 to 15, m is from 0 to 20, n is from 0 to 18,o is from 0 to 20 and, p is from 0 to 20, with the proviso that m+n+o+pis equal to or greater than
 2. 16. The filled elastomer composition ofclaim 5 wherein in mercaptofunctional silane (c) d is 2 to 4, e is 2 to4, f is 2 to 4, m is 0 to 5, n is 0 to 4, o is 0 to 5 and p is 0 to 5.17. The filled elastomer composition of claims 6 wherein inmercaptofunctional silane (c) d is 2, e is 2, f is 3, m is 1 or 2, n is1 or 2, o is 1 or 2 and p is 0 to
 2. 18. The filled elastomercomposition of claim 1 wherein mercaptofunctional silane (c) is at leastone member selected from the group consisting of3-(2-{3-[2-(3-mercapto-propyl)-5-methyl-[1,3,2]dioxasilinan-2-yloxy]-2-methyl-propoxy}-5-methyl-[1,3,2]dioxasilinan-2-yl)-propane-1-thiol;3-(2-{3-[2-(3-mercapto-propy)-4,4,6-trimethyl-[1,3,2]dixasilinan-2-yloxy]-2-methyl-propoxy}-4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yl)-propane-thiol;3-(2-{3-[2-(3-mercapto-propyl)-4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yloxy]-1,1-dimethyl-butoxy}-4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yl)-propane-1-thiol;3-({3-[2-mercapto-propyl)-5-methyl-[1,3,2]dioxasilinan-yloxy]2-methyl-propoxy}-bis-[3-hydroxy-2-methyl-propoxy]-silanyl)-propane-1-thiol;3-[{3-[{3-bis-(3-hydroxy-2-methyl-propyl)-(3-mercapt-propyl)-silanyloxy]-1-methyl-propoxy}-(3-hydroxy-2-methyl-propoxy)-(3-mercapto-propyl)-silanyloxy]-2-methyl-propan-1-ol;3-[[3-((3-hydroxy-3-methyl-propoxy)-3-mercapto-propyl)-{3-[2-(3-mercapto-propyl)-5-methyl-[1,3,2]dioxasilinan-2-yloxy]-1-methyl-propoxy}-silanyloxy)-2-methyl-propoxy-(3-hydroxy-2-methyl-propoxy)-3-mercapto-propyl)-silanyl]-2-methylpropan-1-ol;3-(2-{3-[2-(3-mercapato-butyl)-[1,3,2]dioxasilinan-2-yloxy]-propoxy}-[1,3,2]dioxasilinan-2-yl)-butane-1-thiol;3-(2-{3-[2-(3-mercapto-phenyl)-4,4,6-trimethyl-[1,3,2]dixasilinan-2-yloxy]-2-methyl-propoxy}-4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yl)-3-benzene-thiol;3-(2-{3-[2-(3-mercapto-cyclohexyl)-4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yloxy]-1,1-dimethyl-butoxy}4,4,6-trimethyl-[1,3,2]dioxasilinan-2-yl)-cyclohexane-1-thiol;3-({3-[2-mercapto-methyl)-5-methyl-[1,3,2]dioxasilinan-2-yloxy]-2-methyl-propoxy}-diethoxy]-silanyl)-methane-1-thiol;3-[{3-[{3-bis-(3-hydroxy-2,2-dimethyl-propyl)-(3-mercapt-propyl)-silanyloxy]-2,2-dimethyl-propoxy}-(3-hydroxy-2,2-dimethyl-propoxy)-(3-mercapto-propyl)-silanyloxy]-2,2-dimethyl-propan-1-ol;3-[[3-((3-hydroxy-3-phenyl-propoxy)-3-mercapto-propyl)-{3-[2-(3-mercapto-propyl)-5-phenyl-[1,3,2]dioxasilinan-2-yloxy]-2-phenyl-1-propoxy}-silanyloxy)-2-phenyl-propoxy-(3-hydroxy-2-phenyl-propoxy)-3-mercapto-propyl)-silanyl]-2-phenylpropan-1-ol;3-[{3-[(methyl)-(3-hydroxy-2-methyl-propoxy)-(3-mercapto-propyl)-silanyloxy]-2-methyl-propoxy}-methyl)-(3-mercapto-propyl)-silanyloxy]2-methyl-propan-1-ol.19. The filled elastomer composition of claim 1 containing from about 30to about 98 weight percent of rubber component (a), from about 2 toabout 70 weight percent particulate filler (b) and from about 0.2 toabout 20 weight percent mercaptofunctional silane (c).
 20. The filledelastomer composition of claim 1 containing from about 50 to about 95weight percent of rubber component (a), from about 5 to about 50 weightpercent particulate filler (b) and from about 0.5 to about 50 weightpercent mercaptofunctional silane (c).
 21. The filled elastomercomposition of claim 1 containing from about 60 to about 80 weightpercent of rubber component (a), from about 20 to about 40 weightpercent particulate filler (b) and from about 2 to about 10 weightpercent mercaptofunctional silane (c).
 22. The filled elastomercomposition of claim 1 further comprising (d) at least one curative; (e)at least one polyhydroxyl-containing compound produced in situ from thehydrolysis of mercaptofunctional silane (a) and/or separately added tothe composition; and (f) optionally, at least one accelerator.
 23. Anarticle of manufacture at least one component of which is the curedfilled elastomer composition of claim
 1. 24. The article of manufactureof claim 23 selected from the group consisting of tire, shoe sole, hose,seal, gasket, cable jacket, conveyer belt and power transmission belt.25. A process for making a filled elastomer composition which comprises:a) mixing: (i) at least one rubber component, (ii) at least oneparticulate filler, and (iii) at least one mercaptofunctional silane ofFormula (1) of claim 1, supra; b) optionally mixing: (iv) at least onecurative and/or (v) at least one accelerator and/or (vi) at least onepolyhydroxy-containing compound into the composition resulting from step(a); c) optionally molding the composition resulting from step (b); and,d) optionally curing the composition resulting from step (b) and step(c).
 26. The process of claim 25 wherein at least a portion ofparticulate filler (ii) is pretreated with at least a portion ofmercaptofunctional silane (iii) prior to their mixture with rubbercomponent (i), the resulting treated filler being mixed with rubbercomponent together with, or in the absence of, additional particulatefiller (ii) and/or mercapto functional silane (iii).
 27. The process ofclaim 26 wherein treated filler contains mercaptofunctional silane (iii)in admixture therewith and/or chemically bonded thereto.
 28. A processfor making a rubber composition which comprises: a) thermomechanicallymixing, in at least one preparatory mixing operation, to a temperatureof from about 140° C. to about 180° C., for a total mixing time of fromabout 1 to about 20 minutes for such mixing operation(s): i) about 100parts by weight of at least one sulfur vulcanizable rubber selected fromthe group consisting of conjugated diene homopolymers and copolymers andcopolymers of at least one conjugated diene and aromatic vinyl compound,ii) from about 5 to about 100 parts by weight of particulate filler,wherein the filler preferably contains from 0 to about 85 weight percentcarbon black, and iii) from about 0.05 to about 20 parts by weightfiller of at least one mercaptofunctional silane of Formula (1) of claim1; b) blending the mixture from step (a), in a final thermomechanicalmixing step at a temperature of from about 50° C. to about 130° C. for atime sufficient to blend the rubber, and a curing agent at 0 to 5 partsby weight; and, c) optionally curing said mixture at a temperature inthe range of from about 130 to about 200° C. for a period of from about5 to about 60 minutes.
 29. The process of claim 28 wherein in step (b),at least one polyhydroxy-containing compound is also blended with themixture from step (a).